Myths and other old wives tales regarding PC hardware
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PsychoFish
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Ok, so first things first. The PSU Wattage is a perfectly fine way at looking at a PSU to determine if it may meet your requirements. There are some gotchas to take into account.
Gotcha #1 : Capacitor aging
Capacitors will age, it's just the way things go. The exact percentage will depend on the overall build quality of the PSU, the components used and your usage and load patterns. a good "rule of thumb" is to factor in a 10% per year reduction in output of the PSU if it has been used 24/7 at around 50% usage. This basically means that your 1000W monster PSU will at peak output push around 900W around the end of year 1 and 810W around the end of year two WORST CASE. Capacitor aging is unfortunately NOT LINEAR and could be as low as 1% per year. Case in point is my Coolermaster 750W PSU that is about 3-4 years old and will only push around 700W currently which is well above the expected ~500W if 10% year on year aging is taken into account.
Gotcha #2 : Specifications (aka why a cheap 1000W PSU wont work, but a good quality 550W will work fine)
Technically, the power supply in most PCs is described as a constant voltage switching power supply unit (PSU), which is defined as follows Constant voltage means the power supply puts out the same voltage to the computer’s internal components, no matter the voltage of AC current running it or the capacity (wattage) of the power supply. Switching refers to the design and power regulation technique that most suppliers use. Compared to other types of power supplies, this design provides an efficient and inexpensive power source and generates a minimum amount of heat. It also maintains a small size and
low price.
The PSU normally supplies +3.3 V, +5 V, and +12 V to the system. These voltages are often called rails, referring to the fact that although there are multiple wires carrying a specific voltage, they are normally tied to a single rail (or tap) in the PSU. Multiple wires are used because, if all of the current were carried over a single wire, the wire and the terminals, connectors, and even the traces on the circuit boards would all have to be extremely large and thick to handle the load. Instead, it is cheaper and more efficient to spread the load out among multiple smaller and thinner wires.
The digital electronic components and circuits in the system (motherboard, adapter cards, and disk drive logic boards) typically use the +3.3 V or +5 V power, and the motors (disk drive motors and any fans) use the +12 V power. In addition, voltage regulators on the motherboard or in other components convert these standard voltages to others as necessary.
You can think of each rail as a separate power circuit, kind of like a power supply within the power supply. Normally each rail is rated for a specified maximum amount of current in amperes. Because the extreme amount of 12 V current required by newer CPU voltage regulators and high-end video cards can exceed the output of common 12 V rails, some power supply designs use multiple +12 V rails. This means that essentially they have two or more separate 12 V circuits internally, with some wires tapping off of one circuit and others tapping off of another. Unfortunately, this can lead to power problems, especially if you fail to balance the loads on both rails or to ensure you don’t exceed the load capacity on one or the other. In other words, it is far better to have a single 12 V rail that can supply 40 amps than two 12 V rails supplying 20 amps each because with the single rail you don’t have to worry which connectors derive power from which rail and then try to ensure that you don’t overload one or the other.
Whereas the +3.3 V, +5 V, and +12 V rails are technically independent inside the power supply, many cheaper designs have them sharing some circuitry, making them less independent than they should be. This manifests itself in voltage regulation problems in which a significant load on one rail causes a voltage drop on the others. Components such as processors and video cards can vary their power consumption greatly by their activity. Transitioning from sitting at the Windows desktop to loading a 3D game can cause both the processor and video card to more than double the draw on the +12 V rail. On some cheaper power supplies, this can cause the voltages on the other rails to fall out of spec (drop greater than 5%), making the system crash. Better-designed power supplies feature truly independent rails with tighter regulation in the 1% to 3% range.
The power supply must deliver a good, steady supply of DC power so the system can operate properly. Devices that run on voltages other than these directly must then be indirectly powered through on-board voltage regulators, which take the 5 V or 12 V from the power supply and convert that to the lower voltages required by various components. For example, older DDR (double data rate) dual inline memory modules (DIMMs) and Rambus inline memory modules (RIMMs) require 2.5 V, whereas DDR2 and DDR3 DIMMs require 1.8 V and 1.5 V, legacy AGP 4x/8x cards require 1.5 V, and current PCI Express cards use only 0.8 V differential signaling—all of which are supplied by simple on-board regulators. Processors also require a variety of voltages (as low as 1.3 V or less) that are supplied by a sophisticated voltage regulator module (VRM) that is either built into or plugged into the motherboard. You’ll commonly find three or more different voltage regulator circuits on a modern motherboard.
If you look at a specification sheet for a typical PC power supply, you can see that the supply generates not only +3.3 V, +5 V, and +12 V, but also –12 V and possibly –5 V. Although –12 V and (possibly) –5 V are supplied to the motherboard via the power supply connectors, the motherboard normally uses only the +3.3 V, +5 V, and +12 V. If present, the –5 V is simply routed to the ISA bus on pin B5 so any ISA cards can use it, even though very few ever have. However, as an example, the analog data separator circuits found in older floppy controllers did use –5 V. The motherboard logic typically doesn’t use –12 V either; however, it might be used in some board designs for serial port or local area network (LAN) circuits.
The positive voltages seemingly power everything in the system (logic and motors), so what are the negative voltages used for? The answer is, not much! In fact, –5 V was removed from the ATX12V 1.3 and later specifications. The only reason it remained in most power supply designs for many years is that –5 V was required on the ISA bus for full backward compatibility. Because modern PCs no longer include ISA slots, the –5 V signal was deemed as no longer necessary. However, if you are installing a new power supply in a system with an older motherboard that incorporates ISA bus slots, you want a supply that does include the –5 V signal.
Note: The load placed on the –12 V output by an integrated LAN adapter is small. For example, the integrated 10/100 Ethernet adapter in the Intel D815EEAL motherboard uses only 10 mA of +12 V and 10 mA of –12 V (0.01 amps each) to operate.
Although older serial port circuits used +/–12 V outputs, today most run only on +3.3 V or +5 V.
The main function of the +12 V power is to run disk drive motors as well as the higher-output processor voltage regulators in some of the newer boards. Usually, a large amount of +12 V current is available from the power supply, especially in those designed for systems with a large number of drive bays (such as in a tower configuration). Besides disk drive motors and newer CPU voltage regulators, the +12 V supply is used by any cooling fans in the system—which, of course, should always be running. A single cooling fan can draw between 100 mA and 250 mA (0.1–0.25 amps); however, most newer fans use the lower 100 mA figure. Note that although most fans in desktop systems run on +12 V, portable systems can use fans that run on +5 V or even +3.3 V.
Systems with modern form factors based on the ATX or BTX standards include another special signal. This feature, called PS_ON, can turn the power supply (and thus the system) on or off via software. It is sometimes known as the soft-power feature. PS_ON is most evident when you use it with an operating system (OS) such as Windows that supports the Advanced Power Management (APM) or Advanced Configuration and Power Interface (ACPI) specification. When you shut down a PC from the Start menu, Windows automatically turns off the computer after it completes the OS shutdown sequence. A system without this feature only displays a message that it’s safe or ready for you to shut down the computer manually.
TLDR version : look at the sticker on the side of your PSU and take each specified rail (12V, 5V, 3V). Then for each rail multiply the Ampere rating with the Volt rating to get the electric power (Watts) for the rail. Do this for all specified rails, then add up the numbers. This should be equal to or less than your PSUs overall Wattage rating (but will never be
). Also, good quality PSUs will have MULTIPLE & SEPERATE 12V and 5V rails.
Example: Coolermaster GX750 - CM Storm Edition
AC INPUT : 100-240V~ 12-6A 60-50Hz
DC OUTPUT :
+3.3V @ 22A rated at 120W (72.6 W actual)(NOTE that the 3.3V and 5V share the SAME RAIL)
+5V @ 22A rated at 120W (110 W actual) (shared with the 3.3V rail)
Actual @ maximum : 72.6W +110W = 182.6 W which is 60W more than the rail can handle
12V @ 62A rated at 744W (actual is 744W)
Now add 744W + 182.6W = 926.6W which is 176.6 W more than what the PSU is rated at.
So to then work out EXACTLY what is needed, take the MAX wattage requirement of each component : CPU + Memory + CD-ROM/DVD-ROM/Blu-Ray + HDD + fans, split those into their rail requirements, then see if you're maxing out your PSU.
Gotcha #1 : Capacitor aging
Capacitors will age, it's just the way things go. The exact percentage will depend on the overall build quality of the PSU, the components used and your usage and load patterns. a good "rule of thumb" is to factor in a 10% per year reduction in output of the PSU if it has been used 24/7 at around 50% usage. This basically means that your 1000W monster PSU will at peak output push around 900W around the end of year 1 and 810W around the end of year two WORST CASE. Capacitor aging is unfortunately NOT LINEAR and could be as low as 1% per year. Case in point is my Coolermaster 750W PSU that is about 3-4 years old and will only push around 700W currently which is well above the expected ~500W if 10% year on year aging is taken into account.
Gotcha #2 : Specifications (aka why a cheap 1000W PSU wont work, but a good quality 550W will work fine)
Technically, the power supply in most PCs is described as a constant voltage switching power supply unit (PSU), which is defined as follows Constant voltage means the power supply puts out the same voltage to the computer’s internal components, no matter the voltage of AC current running it or the capacity (wattage) of the power supply. Switching refers to the design and power regulation technique that most suppliers use. Compared to other types of power supplies, this design provides an efficient and inexpensive power source and generates a minimum amount of heat. It also maintains a small size and
low price.
The PSU normally supplies +3.3 V, +5 V, and +12 V to the system. These voltages are often called rails, referring to the fact that although there are multiple wires carrying a specific voltage, they are normally tied to a single rail (or tap) in the PSU. Multiple wires are used because, if all of the current were carried over a single wire, the wire and the terminals, connectors, and even the traces on the circuit boards would all have to be extremely large and thick to handle the load. Instead, it is cheaper and more efficient to spread the load out among multiple smaller and thinner wires.
The digital electronic components and circuits in the system (motherboard, adapter cards, and disk drive logic boards) typically use the +3.3 V or +5 V power, and the motors (disk drive motors and any fans) use the +12 V power. In addition, voltage regulators on the motherboard or in other components convert these standard voltages to others as necessary.
You can think of each rail as a separate power circuit, kind of like a power supply within the power supply. Normally each rail is rated for a specified maximum amount of current in amperes. Because the extreme amount of 12 V current required by newer CPU voltage regulators and high-end video cards can exceed the output of common 12 V rails, some power supply designs use multiple +12 V rails. This means that essentially they have two or more separate 12 V circuits internally, with some wires tapping off of one circuit and others tapping off of another. Unfortunately, this can lead to power problems, especially if you fail to balance the loads on both rails or to ensure you don’t exceed the load capacity on one or the other. In other words, it is far better to have a single 12 V rail that can supply 40 amps than two 12 V rails supplying 20 amps each because with the single rail you don’t have to worry which connectors derive power from which rail and then try to ensure that you don’t overload one or the other.
Whereas the +3.3 V, +5 V, and +12 V rails are technically independent inside the power supply, many cheaper designs have them sharing some circuitry, making them less independent than they should be. This manifests itself in voltage regulation problems in which a significant load on one rail causes a voltage drop on the others. Components such as processors and video cards can vary their power consumption greatly by their activity. Transitioning from sitting at the Windows desktop to loading a 3D game can cause both the processor and video card to more than double the draw on the +12 V rail. On some cheaper power supplies, this can cause the voltages on the other rails to fall out of spec (drop greater than 5%), making the system crash. Better-designed power supplies feature truly independent rails with tighter regulation in the 1% to 3% range.
The power supply must deliver a good, steady supply of DC power so the system can operate properly. Devices that run on voltages other than these directly must then be indirectly powered through on-board voltage regulators, which take the 5 V or 12 V from the power supply and convert that to the lower voltages required by various components. For example, older DDR (double data rate) dual inline memory modules (DIMMs) and Rambus inline memory modules (RIMMs) require 2.5 V, whereas DDR2 and DDR3 DIMMs require 1.8 V and 1.5 V, legacy AGP 4x/8x cards require 1.5 V, and current PCI Express cards use only 0.8 V differential signaling—all of which are supplied by simple on-board regulators. Processors also require a variety of voltages (as low as 1.3 V or less) that are supplied by a sophisticated voltage regulator module (VRM) that is either built into or plugged into the motherboard. You’ll commonly find three or more different voltage regulator circuits on a modern motherboard.
If you look at a specification sheet for a typical PC power supply, you can see that the supply generates not only +3.3 V, +5 V, and +12 V, but also –12 V and possibly –5 V. Although –12 V and (possibly) –5 V are supplied to the motherboard via the power supply connectors, the motherboard normally uses only the +3.3 V, +5 V, and +12 V. If present, the –5 V is simply routed to the ISA bus on pin B5 so any ISA cards can use it, even though very few ever have. However, as an example, the analog data separator circuits found in older floppy controllers did use –5 V. The motherboard logic typically doesn’t use –12 V either; however, it might be used in some board designs for serial port or local area network (LAN) circuits.
The positive voltages seemingly power everything in the system (logic and motors), so what are the negative voltages used for? The answer is, not much! In fact, –5 V was removed from the ATX12V 1.3 and later specifications. The only reason it remained in most power supply designs for many years is that –5 V was required on the ISA bus for full backward compatibility. Because modern PCs no longer include ISA slots, the –5 V signal was deemed as no longer necessary. However, if you are installing a new power supply in a system with an older motherboard that incorporates ISA bus slots, you want a supply that does include the –5 V signal.
Note: The load placed on the –12 V output by an integrated LAN adapter is small. For example, the integrated 10/100 Ethernet adapter in the Intel D815EEAL motherboard uses only 10 mA of +12 V and 10 mA of –12 V (0.01 amps each) to operate.
Although older serial port circuits used +/–12 V outputs, today most run only on +3.3 V or +5 V.
The main function of the +12 V power is to run disk drive motors as well as the higher-output processor voltage regulators in some of the newer boards. Usually, a large amount of +12 V current is available from the power supply, especially in those designed for systems with a large number of drive bays (such as in a tower configuration). Besides disk drive motors and newer CPU voltage regulators, the +12 V supply is used by any cooling fans in the system—which, of course, should always be running. A single cooling fan can draw between 100 mA and 250 mA (0.1–0.25 amps); however, most newer fans use the lower 100 mA figure. Note that although most fans in desktop systems run on +12 V, portable systems can use fans that run on +5 V or even +3.3 V.
Systems with modern form factors based on the ATX or BTX standards include another special signal. This feature, called PS_ON, can turn the power supply (and thus the system) on or off via software. It is sometimes known as the soft-power feature. PS_ON is most evident when you use it with an operating system (OS) such as Windows that supports the Advanced Power Management (APM) or Advanced Configuration and Power Interface (ACPI) specification. When you shut down a PC from the Start menu, Windows automatically turns off the computer after it completes the OS shutdown sequence. A system without this feature only displays a message that it’s safe or ready for you to shut down the computer manually.
TLDR version : look at the sticker on the side of your PSU and take each specified rail (12V, 5V, 3V). Then for each rail multiply the Ampere rating with the Volt rating to get the electric power (Watts) for the rail. Do this for all specified rails, then add up the numbers. This should be equal to or less than your PSUs overall Wattage rating (but will never be
). Also, good quality PSUs will have MULTIPLE & SEPERATE 12V and 5V rails.Example: Coolermaster GX750 - CM Storm Edition
AC INPUT : 100-240V~ 12-6A 60-50Hz
DC OUTPUT :
+3.3V @ 22A rated at 120W (72.6 W actual)(NOTE that the 3.3V and 5V share the SAME RAIL)
+5V @ 22A rated at 120W (110 W actual) (shared with the 3.3V rail)
Actual @ maximum : 72.6W +110W = 182.6 W which is 60W more than the rail can handle
12V @ 62A rated at 744W (actual is 744W)
Now add 744W + 182.6W = 926.6W which is 176.6 W more than what the PSU is rated at.
So to then work out EXACTLY what is needed, take the MAX wattage requirement of each component : CPU + Memory + CD-ROM/DVD-ROM/Blu-Ray + HDD + fans, split those into their rail requirements, then see if you're maxing out your PSU.
PsychoFish
New member
Just to stack up:
Example Antec TruePower Classic TP-750C
AC INPUT : 100-240V~ 12-6A 60-50Hz
DC OUTPUT :
+3.3V @ 20A rated at 100W (66 W actual)(NOTE that the 3.3V and 5V share the SAME RAIL)
+5V @ 20A rated at 100W ( 100 W actual) (shared with the 3.3V rail)
Actual @ maximum : 66W +100W = 166 W which is 66W more than the rail can handle
2x 12V @ 35A each rated at 744W (combined) (actual is 420W + 420W)
Now add 840 + 166W = 1006 W which is 256 W more than what the PSU is rated at.
Important to note here is that even though the PSU has two rails and a higher Amperage rating than the Coolermaster the Max throughput of the rails are combined, so you'll be able to load EXACTLY the same amount on the 12V rail as the Coolermaster.
Example Antec TruePower Classic TP-750C
AC INPUT : 100-240V~ 12-6A 60-50Hz
DC OUTPUT :
+3.3V @ 20A rated at 100W (66 W actual)(NOTE that the 3.3V and 5V share the SAME RAIL)
+5V @ 20A rated at 100W ( 100 W actual) (shared with the 3.3V rail)
Actual @ maximum : 66W +100W = 166 W which is 66W more than the rail can handle
2x 12V @ 35A each rated at 744W (combined) (actual is 420W + 420W)
Now add 840 + 166W = 1006 W which is 256 W more than what the PSU is rated at.
Important to note here is that even though the PSU has two rails and a higher Amperage rating than the Coolermaster the Max throughput of the rails are combined, so you'll be able to load EXACTLY the same amount on the 12V rail as the Coolermaster.
PsychoFish
New member
PsychoFish
New member
And last one one this...
80 Plus Energy Efficiency Rating Differences
This refers to the output-to-input ratio of the power supply and refers to PSUs that are 80% efficient or better at converting input to output. You may have encountered "80 Plus" Bronze, Silver, Gold, or Platinum ratings in the past.
This chart (source) shows how efficient the certifications claim PSUs are at given loads (20% max load, 50% max load, and max load). At 20% load, the efficiency numbers tend to be lower due to disproportionate power consumption (to power utilization) being used in the transformation process from AC-to-DC. We see a decrease in efficiency again at max load, where efficiency drops by the heat generation incurred by maximum power output.
If you're in North America, chances are that you use 120VAC (Volts in Alternating Current), while those in Africa and Europe (and parts of Asia) are likely using the much more efficient 230VAC from the wall. There's nothing to do about this - it's just one or the other, but the efficiency curve will generally favor 230VAC.
In terms of what this means for the PSU, you'll either have a manually-switched or automatically-switched power supply; manually-switched devices have a discrete red switch on the backside that reads 115 (for the US) and 230 (for most of the world). If you have an auto-switched device, you're golden no matter where you go. If it's manual, always play it safe and check to ensure the switch is in the position corresponding to your country's power infrastructure.
On a side note, laptop power adapters are almost exclusively auto switched.
80 Plus Energy Efficiency Rating Differences
This refers to the output-to-input ratio of the power supply and refers to PSUs that are 80% efficient or better at converting input to output. You may have encountered "80 Plus" Bronze, Silver, Gold, or Platinum ratings in the past.
This chart (source) shows how efficient the certifications claim PSUs are at given loads (20% max load, 50% max load, and max load). At 20% load, the efficiency numbers tend to be lower due to disproportionate power consumption (to power utilization) being used in the transformation process from AC-to-DC. We see a decrease in efficiency again at max load, where efficiency drops by the heat generation incurred by maximum power output.
If you're in North America, chances are that you use 120VAC (Volts in Alternating Current), while those in Africa and Europe (and parts of Asia) are likely using the much more efficient 230VAC from the wall. There's nothing to do about this - it's just one or the other, but the efficiency curve will generally favor 230VAC.
In terms of what this means for the PSU, you'll either have a manually-switched or automatically-switched power supply; manually-switched devices have a discrete red switch on the backside that reads 115 (for the US) and 230 (for most of the world). If you have an auto-switched device, you're golden no matter where you go. If it's manual, always play it safe and check to ensure the switch is in the position corresponding to your country's power infrastructure.
On a side note, laptop power adapters are almost exclusively auto switched.
PsychoFish
New member
What CPU, memory and graphics card you running?
MalicE
Party time! Excellent!
i5 2.4ghz, 8gb ddr3 ram, 1 SSD, 2 sata (3rd is stull unpluged) and a nvidia 560Ti
oh yeah and a dvd writer
and a whole lot of USB devices
PsychoFish
New member
i5 2.4ghz, 8gb ddr3 ram, 1 SSD, 2 sata (3rd is stull unpluged) and a nvidia 560Ti
oh yeah and a dvd writer
and a whole lot of USB devices
Yeah, your 480W is plenty for your rig. What blows my rig to a 750W PSU is the SLI config and the whole cooling setup with fan controller.
So that means i fell for this marketing Bs and actually over provided for my rig ?
I have a msi gaming m7
6700K
16Gb DDR 4 ram
5 Sata HDD
1 Sata SSD
980 GTX
I plan to sli mid next year . And was told it will be a power hungry beast and was told i need a 1000W Plus PSU. I went for the Antec 1000W HCP and seems a 850 would've worked for me aswell. Also a drop to 850 and From platinum to gold i could have saved a few hundred bucks.
I have a msi gaming m7
6700K
16Gb DDR 4 ram
5 Sata HDD
1 Sata SSD
980 GTX
I plan to sli mid next year . And was told it will be a power hungry beast and was told i need a 1000W Plus PSU. I went for the Antec 1000W HCP and seems a 850 would've worked for me aswell. Also a drop to 850 and From platinum to gold i could have saved a few hundred bucks.
PsychoFish
New member
Hate to break it to you, but you could pull it off with a 600W PSU.
If you go SLI I'd recommend nothing less than a 750W PSU
PsychoFish
New member
Shameless copy and paste...but here goes
Myth: Frames rate is the indicator of graphics performance
Common wisdom suggests that for a game to be playable, it should run at 30 frames per second or more. Some folks believe lower frame rates are still alright, and others insist that 30 FPS is far too low.
In the debate, however, it's not always reinforced that FPS is just a rate, and there is a host of complexity behind it. Most notably, while the frame rate of a movie is constant, a rendered game varies over time and is consequently expressed as an average. Variation is a byproduct of the horsepower required to process any given scene, and as the on-screen content changes, so does frame rate.
The simple point is that there is more to quality of a gaming experience than the instantaneous (or average) rate at which frames are rendered. The consistency of their delivery is an additional factor. Imagine traveling on a highway at a constant 100 km/h compared to the same trip at an average of 100km/h, spending a lot more time switching between accelerator and brake. You reach your destination in roughly the same amount of time, but the experience is quite a bit different.
Myths: V-sync should always be enabled. V-sync should always be disabled.
If you play first-person shooter games competitively, and/or have issues with perceived input lag, and/or if your system cannot sustain at least 60 FPS in a given title, and/or you're benchmarking your graphics card, then you should turn V-sync off.
If none of the above applies to you and you experience significant screen tearing, then you should turn V-sync on.
If you own a gaming-oriented 120/144 Hz display (if you have one, there's a good chance you bought it specifically for its higher refresh rate): You should consider leaving V-sync on only when playing older games, where you experience a sustained >120 FPS and you are experiencing screen tearing
Myth: Graphics Cards Affect Input Lag
It takes time for what happens in a game to show up on your screen. It takes from for you to react. And it takes time for your mouse and keyboard inputs to register. Somewhat improperly, the delay between you issuing a command and the on-screen action is commonly called input lag. So, if you press the trigger in a first-person shooter and your weapon fires .1 seconds later, your input lag is effectively 100 milliseconds.
Human reaction times to visual inputs vary. According to a 1986 U.S. Navy study, the average F-14 fighter pilot reacted to a simple visual stimulus in an average of 223 ms. And it might not seem correct, but human beings actually react faster to sound than visual inputs. Reactions to auditory stimuli tend to be in the ~150 ms range.
Fortunately, no matter how poorly-configured your PC may be, it probably won't hit 200 ms of input lag. So, your personal reaction time remains the biggest influencer of how quickly your character responds in a game.
As differences in input lag increase, however, they increasingly do affect gameplay. Imagine a professional gamer with reflexes comparable to the best fighter pilots at 150 ms. A 50 ms slow-down in input means that person will be 30% slower (that's four frames on a 60 Hz display) than his competition. At the professional level, that's notable.
For mere mortals and for anyone who would rather play Civilization V leisurely than Counter Strike 1.6 competitively, it’s an entirely different story; you can likely ignore input lag altogether.
Here are some of the factors that can worsen input lag, all else being equal:
- Playing on an HDTV (even more so if its game mode is disabled) or playing on an LCD display that performs some form of video processing that cannot be bypassed.
- Playing on LCD displays, which employ higher-response time IPS panels (5-7 ms G2G typical), versus TN+Film panels (1-2 ms GTG possible), versus CRT displays (the fastest available).
- Playing on displays with lower refresh rates; the newest gaming displays support 120 or 144 Hz natively.
- Playing at low frame rates (30 FPS is one frame every 33 ms; 144 FPS is one frame every 7 ms).
- Using a USB-based mouse with a low polling rate. The default 125 Hz is a ~6 ms cycle time, yielding a ~3 ms input lag on average. Meanwhile, gaming mice can go to ~1000 Hz for ~0.5 ms average input lag.
- Using a low-quality keyboard (keyboard input lag is 16 ms typically, but can be higher for poor ones).
- Playing with high render-ahead queues. The default in Direct3D is three frames, or 48 ms at 60 Hz. This figure can be increased to 20 for greater “smoothness†and dropped to one for increased responsiveness at the cost of greater frame time variance and, in some cases, somewhat lower FPS overall. There is no such setting as a zero setting; what zero does is simply reset to the default value of three.
- Playing on a high-latency Internet connection. While this goes beyond what would be defined as input lag, if effectively stacks with it
Factors that do not make a difference include:
- Using a PS/2 or USB keyboard
- Using a wireless or wired network connection
- Enabling SLI or CrossFire. The longer render queues required to enable these technologies are generally compensated by higher frame throughput.
Myth: Graphics cards with 2 GB of memory are faster than those with 1 GB
What does having more video memory actually help, then? In order to answer that, we need to know what graphics memory is used for. This is simplifying a bit, but it helps with:
- Loading textures
- Holding the frame buffer
- Holding the depth buffer ("Z Buffer")
- Holding other assets that are required to render a frame (shadow maps, etc.)
Of course, the size of the textures getting loaded into memory depends on the game you're playing and its quality preset. As an example, the Skyrim high-resolution texture pack includes 3 GB of textures. Most applications dynamically load and unload textures as they're needed, though, so not all textures need to reside in graphics memory. The textures required to render a particular scene do need to be in memory, however.
The frame buffer is used to store the image as it is rendered, before or during the time it is sent to the display. Thus, its memory footprint depends on the output resolution (an image at at 1920x1080x32 bpp is ~8.3 MB; a 4K image at 3840x2160x32 is ~33.2 MB), the number of buffers (at least two; rarely three or more).
As specific anti-aliasing modes (FSAA, MSAA, CSAA, CFAA, but not FXAA or MLAA) effectively increase the number of pixels that need to be rendered, they proportionally increase overall required graphics memory. Render-based anti-aliasing in particular has a massive impact on memory usage, and that grows as sample size (2x, 4x, 8x, etc) increases. Additional buffers also occupy graphics memory.
So, a graphics card with more memory allows you to:
- Play at higher resolutions
- Play at higher texture quality settings
- Play with higher render-based antialiasing settings
Myth: My 120/240/480Hz HDTV is better for gaming than a corresponding 60Hz PC display
Except for 4K displays, almost all HDTVs are limited in resolution to a maximum of 1920x1080. PC displays can go up to 3840x2160.
PC displays can currently take inputs up to 144Hz, while televisions are limited to 60Hz. Don't be fooled by 120, 240 or 480Hz marketing. Those televisions are still limited to 60Hz input signals
Compared to PC display standards, HDTV input lag can be massive (50, sometimes even 75 ms). Summed up with all additional lag contributors in a system, that’s almost certainly noticeable. If you really must play on an HDTV, make sure its "game mode" is enabled. Also, you may want to disable its 120Hz setting entirely
Myth: Frames rate is the indicator of graphics performance
Common wisdom suggests that for a game to be playable, it should run at 30 frames per second or more. Some folks believe lower frame rates are still alright, and others insist that 30 FPS is far too low.
In the debate, however, it's not always reinforced that FPS is just a rate, and there is a host of complexity behind it. Most notably, while the frame rate of a movie is constant, a rendered game varies over time and is consequently expressed as an average. Variation is a byproduct of the horsepower required to process any given scene, and as the on-screen content changes, so does frame rate.
The simple point is that there is more to quality of a gaming experience than the instantaneous (or average) rate at which frames are rendered. The consistency of their delivery is an additional factor. Imagine traveling on a highway at a constant 100 km/h compared to the same trip at an average of 100km/h, spending a lot more time switching between accelerator and brake. You reach your destination in roughly the same amount of time, but the experience is quite a bit different.
Myths: V-sync should always be enabled. V-sync should always be disabled.
If you play first-person shooter games competitively, and/or have issues with perceived input lag, and/or if your system cannot sustain at least 60 FPS in a given title, and/or you're benchmarking your graphics card, then you should turn V-sync off.
If none of the above applies to you and you experience significant screen tearing, then you should turn V-sync on.
If you own a gaming-oriented 120/144 Hz display (if you have one, there's a good chance you bought it specifically for its higher refresh rate): You should consider leaving V-sync on only when playing older games, where you experience a sustained >120 FPS and you are experiencing screen tearing
Myth: Graphics Cards Affect Input Lag
It takes time for what happens in a game to show up on your screen. It takes from for you to react. And it takes time for your mouse and keyboard inputs to register. Somewhat improperly, the delay between you issuing a command and the on-screen action is commonly called input lag. So, if you press the trigger in a first-person shooter and your weapon fires .1 seconds later, your input lag is effectively 100 milliseconds.
Human reaction times to visual inputs vary. According to a 1986 U.S. Navy study, the average F-14 fighter pilot reacted to a simple visual stimulus in an average of 223 ms. And it might not seem correct, but human beings actually react faster to sound than visual inputs. Reactions to auditory stimuli tend to be in the ~150 ms range.
Fortunately, no matter how poorly-configured your PC may be, it probably won't hit 200 ms of input lag. So, your personal reaction time remains the biggest influencer of how quickly your character responds in a game.
As differences in input lag increase, however, they increasingly do affect gameplay. Imagine a professional gamer with reflexes comparable to the best fighter pilots at 150 ms. A 50 ms slow-down in input means that person will be 30% slower (that's four frames on a 60 Hz display) than his competition. At the professional level, that's notable.
For mere mortals and for anyone who would rather play Civilization V leisurely than Counter Strike 1.6 competitively, it’s an entirely different story; you can likely ignore input lag altogether.
Here are some of the factors that can worsen input lag, all else being equal:
- Playing on an HDTV (even more so if its game mode is disabled) or playing on an LCD display that performs some form of video processing that cannot be bypassed.
- Playing on LCD displays, which employ higher-response time IPS panels (5-7 ms G2G typical), versus TN+Film panels (1-2 ms GTG possible), versus CRT displays (the fastest available).
- Playing on displays with lower refresh rates; the newest gaming displays support 120 or 144 Hz natively.
- Playing at low frame rates (30 FPS is one frame every 33 ms; 144 FPS is one frame every 7 ms).
- Using a USB-based mouse with a low polling rate. The default 125 Hz is a ~6 ms cycle time, yielding a ~3 ms input lag on average. Meanwhile, gaming mice can go to ~1000 Hz for ~0.5 ms average input lag.
- Using a low-quality keyboard (keyboard input lag is 16 ms typically, but can be higher for poor ones).
- Playing with high render-ahead queues. The default in Direct3D is three frames, or 48 ms at 60 Hz. This figure can be increased to 20 for greater “smoothness†and dropped to one for increased responsiveness at the cost of greater frame time variance and, in some cases, somewhat lower FPS overall. There is no such setting as a zero setting; what zero does is simply reset to the default value of three.
- Playing on a high-latency Internet connection. While this goes beyond what would be defined as input lag, if effectively stacks with it
Factors that do not make a difference include:
- Using a PS/2 or USB keyboard
- Using a wireless or wired network connection
- Enabling SLI or CrossFire. The longer render queues required to enable these technologies are generally compensated by higher frame throughput.
Myth: Graphics cards with 2 GB of memory are faster than those with 1 GB
What does having more video memory actually help, then? In order to answer that, we need to know what graphics memory is used for. This is simplifying a bit, but it helps with:
- Loading textures
- Holding the frame buffer
- Holding the depth buffer ("Z Buffer")
- Holding other assets that are required to render a frame (shadow maps, etc.)
Of course, the size of the textures getting loaded into memory depends on the game you're playing and its quality preset. As an example, the Skyrim high-resolution texture pack includes 3 GB of textures. Most applications dynamically load and unload textures as they're needed, though, so not all textures need to reside in graphics memory. The textures required to render a particular scene do need to be in memory, however.
The frame buffer is used to store the image as it is rendered, before or during the time it is sent to the display. Thus, its memory footprint depends on the output resolution (an image at at 1920x1080x32 bpp is ~8.3 MB; a 4K image at 3840x2160x32 is ~33.2 MB), the number of buffers (at least two; rarely three or more).
As specific anti-aliasing modes (FSAA, MSAA, CSAA, CFAA, but not FXAA or MLAA) effectively increase the number of pixels that need to be rendered, they proportionally increase overall required graphics memory. Render-based anti-aliasing in particular has a massive impact on memory usage, and that grows as sample size (2x, 4x, 8x, etc) increases. Additional buffers also occupy graphics memory.
So, a graphics card with more memory allows you to:
- Play at higher resolutions
- Play at higher texture quality settings
- Play with higher render-based antialiasing settings
Myth: My 120/240/480Hz HDTV is better for gaming than a corresponding 60Hz PC display
Except for 4K displays, almost all HDTVs are limited in resolution to a maximum of 1920x1080. PC displays can go up to 3840x2160.
PC displays can currently take inputs up to 144Hz, while televisions are limited to 60Hz. Don't be fooled by 120, 240 or 480Hz marketing. Those televisions are still limited to 60Hz input signals
Compared to PC display standards, HDTV input lag can be massive (50, sometimes even 75 ms). Summed up with all additional lag contributors in a system, that’s almost certainly noticeable. If you really must play on an HDTV, make sure its "game mode" is enabled. Also, you may want to disable its 120Hz setting entirely