DDR3 1600Mhz Memory - different timings

[ChameleonDevil]

I bought 4GB (2x2GB) DDR3 1600Mhz Mushkin CL7 1.65V RAM two years ago, I want to add another DDR3 1600Mhz 8 GB (2x4GB) for now, but with CL9 timings because the price difference between CL7 and CL9 has seemingly jumped to double... I bought CL7 because they were nearly same price then.

So, my question is will the CL7 & CL9 RAM run together? If so, obviously running at the slower timings right?

EDIT : I have to add the RAM Im thinking of is 1.55-1.75V where my originals is @ 1.65V