WOW can't be since the 3 patches are about 200meg together. And even with addons its not even close to 1gig. The only things that could possible make it to 3gigs is to download all the DLC.
just a bit off topic, but i find when my steam patches games it goes through 2-3gb of data (seems like some sort of data verification). Maybe thats how you ended up with a DA 3gb "patch"?