depending upon the card you buy/your 1337 overclocking skills, a 4200 can be faster or at least as fast as the 4600. If I were putting my money down right now I would definately go with the 4200. I recently read a decent article about a 4200 HERE. It also explains the 64m vs 128m battle a bit better. To summarize: 64meg 4200 = 3.5ns 128meg 4200 = 4ns (both assuming you go w/ the MSI card, although most are the same) 64meg 4200 = faster stock, thus overclocks to a greater speed 128meg 4200 = more, thus does better with higher resolutions. (1024 x 768 as explained in the article.) But does have a lower memory clock speed. I'm done rambling, you can read the article if you want
