I think I read about your problem in another forum. Which forums do you visit regularly? Either way, I ran that memcheck, and I get about 132,000,000 available and 128,000,000 free with my GeForce 4 TI 4200. I'm not sure if that program is designed to work with ATI cards. One thing is for sure: that fucking video card shouldn't be running any of those games under 60 frames per second with most of them going well over 100. Something is messed up badly. The RAM can't be slowing it down, and the CPU sure can't either. My only guess is either the video card is fucked up (which is odd considering Sapphire is awesome) or the motherboard is broke.
Try the card in different computers. You said that your friend's 128 MB version had similar results in your PC which really makes me think it's your motherboard. I'd flash the BIOS (carefully) and reinstall the drivers for the chipset yet again, then install the video drivers again. If that doesn't do shit then switch out the RAM if applicable. If that doesn't fix it, I'd say it's the motherboard. Just my look on the situation. If I were in your situation I would have already RMA'ed the video card back or refunded it, but maybe I'm just an RMA whore.
Good luck!
-Lasereth