See I find that Nvidia has just as many problems, because I run a HD 3800 series ATI, and I wont suffer alot of issues Nvidia players suffer in games like New Vegas. But I think those games are made with ATI so that could be why? Overall though Ive been rather happy with my ATI, been using the brand since like 03? And ive never looked back.
Still I think more than likely its my CPU, simply because its still technically a single core processor. But thats simply something I cannot do a whole bunch about at this moment, due to being on a fixed income.
So yeah, just be forewarned that if you try Rift, you may not like how it looks if your computer isn't at least..somewhat up to speed.