i get normal fps in applications running in a small window at high res but in full screen i get like 10% fps.This is the vram problem.
If you run a game windowed with the desktop resolution set to 2560x1600, the game will run at the lower resolution of the window, not the resolution of the desktop.
For example, if the window takes up a quarter of your screen, the game actually runs at 1280x800 - which is why the games run well windowed.
I'm sorry, but you have had many persons telling you that you simply don't have enough vram for your res witt aa/af turned on. I suggest you trust them. You cannot "tweak" your cards into having more vram than what is soldered onto them.