I'm looking at upgrading my GPU from a AMD Radeon HD 6870 to either a AMD Radeon HD 7870 or 7950. but reading around reviews, Some cards come with 2GB GDDR5 and 3GB GDDR5. My current 6870 has 1GB GDDR5, and Iknow it isn't pulling it's leg with BF3 or Crysis 2 (with the DirectX 11 Patch). Its fine for everything else getting perfect 60fps, on high settings, but BF3 and CR2 it hovers around 45fps and dips to 35fps in rough, fast pace scenes with using high/ultra settings on those games. I have 16GB DDR3 1600MHz Corsair memory and an 8 core AMD FX-8120. So theres nothing there I can think of. If a GPU runs out of memory in it's buffer, does it swap, and page back to the page file on the HDD, or swaps out to main system memory?