ive recently installed a geforce fx 5500 card into my comp, replacing the radeon card that was in it. ive been experiencing alot of problems though when in video games(freezing, crashing) and on the windows desktop with mouse cursor lagging. i was reading my install guide for the card and it said that make sure the AGP aperture matches the amount of memory on the video card, which should be 256mb. when i run cpu-z and look under the AGP section of the mainboard tab, it says that the aperture is only 64 mb. could this be the reason why im experiencing these problems and does anyone know how i can change the aperture size? any help is appreciated.