|There are several things to consider when choosing a video card. Some of the more important specs to look for are memory related - type of memory (DDR, DDR2/GDDR2, DDR3/GDDR3, DDR5/GDDR5), amount (256MB, 512MB, 1GB), memory interface (64-bit, 128-bit, 192-bit, 256-bit). When you see a G, it means Graphics, so generally, GDDR3 will be better than DDR3. Look at the speed the memory runs at too.|
You should also look at the number of stream processors supported by the GPU (graphics processing unit). AMD/ATI & nvidia numbers are different so to make a fair comparison, either multiple the nvidia stream processors x 5, or divide the AMD/ATI processors by 5. For example, the nvidia Geforce GT 220 has 48 stream processors so a comparable AMD/ATI card should have to have 240 (48 x 5).
This article should help narrow down your choices:
Best Graphics Cards For The Money: February 2011
Be sure to check the Hierarchy chart at the end of the article for cards not on the recmmended list.