FX 5500 PCI version. the 128mb is fine. The 256 is frivilous memory that gets wasted. I just installed an FX 5500 128mb video card in my friend's brother's computer. It ran Counter Strike: Source pretty well! I was surprised. I was again, very happy with the installation. Super easy. Buy the eVGA model off of zipzoomfly. You'll get free second day shipping and the total cost is 55 bucks.
Ryan