Conclusions
If you're looking at running a single GeForce 8800 GT, the card's default 512MB memory size is easily the best. Doubling the onboard memory to 1GB may make for interesting marketing, but it doesn't improve performance a lick with the games and resolutions we tested. What's more, a single 8800 GT runs out of steam at 1920x1440—if not at lower resolutions—indicating that higher resolutions that might benefit from additional video memory wouldn't yield playable frame rates with single-card configs.

The benefits of 1GB of video memory are also a bust for GeForce 8800 GT SLI configurations, at least at resolutions up to 1920x1440. However, we've seen the 8800 GT 512MB in SLI deliver playable frame rates at 2650x1600 in Quake Wars and Episode 2, so a 1GB SLI config may yield performance benefits there. We've also observed the performance of a 512MB SLI config tank spectacularly in Call of Duty 4 when moving to 2560x1600, suggesting that additional video memory could be of help there, as well.

As for the 256MB variant of the GeForce 8800 GT, well, there's little hope. The 256MB card fared well enough in Quake Wars, but it couldn't keep up at even 1280x1024 in CoD 4 and started to drop off at 1600x1200 in Episode 2. And Crysis? Forget about it.

Given the relatively minor price gap between 256MB and 512MB versions of the GeForce 8800 GT, we see little reason to settle for the 256MB card. You really do need 512MB of memory to make the most of today's games, especially if you want to crank up the eye candy. That said, today's games aren't so demanding that they'll make good use of 1GB of video memory, at least not with the GeForce 8800 GT. Not even Crysis saw a meaningful performance increase with the 1GB cards, suggesting that tomorrow's games may do just fine with 512MB, as well.