Like the GeForce 7800 GT before it, the Nvidia GeForce 7900 GT aims for the price-performance sweet spot. For roughly $300, you'll get a card that beats every other card on the market except for a few that cost $500 and beyond. Frames-per-dollar aside, this card and all of Nvidia's most recent graphics chips have a problem: they don't support as many modern features simultaneously as ATI's cards do. If all you're after is speed, the GeForce 7900 GT is an easy pick, either as a single 3D card or in dual-card SLI mode. But if you're after image quality rather than raw speed, ATI's $250 Radeon X1800 GTO offers an aggressively priced, albeit slower, alternative.
The GeForce 7900 GT is the little brother of Nvidia's top-of-the-line GeForce 7900 GTX. Both have been on the market for two months, and after an initial period of scarcity, online vendors finally have plenty of both cards in stock from Nvidia's board partners.
You'll find the GeForce 7900 GT available only with 256MB of memory. Some partners sell it overclocked for a small premium, usually no more than $50. At its stock speeds, the GeForce 7900 GT features a 450MHz core clock and a 1,320MHz memory clock. Not only are those speeds an increase over the GeForce 7800 GT's (400MHz core, 1,000MHz memory), the 7900 GT is also less expensive than its $450 forebear. Nvidia dropped the price, thanks to a more efficient 90nm manufacturing process, which yields more usable chips per silicon wafer. ATI's comparable chips use the same 90nm process, but they have more features and are thus larger, which explains their higher costs.
As we noted, in both single- and dual-card mode, the GeForce 7900 GT outpaced its closest ATI-based competition, the Radeon X1800 GTO in all of our tests. What we find more interesting is that two $300 7900 GTs in SLI mode run faster than a single $600 Radeon X1900 XTX (check out our F.E.A.R. benchmarks, for example). But despite its strong performance, we can't pick the GeForce 7900 GT as the best all-around graphics card because of what it lacks in features.
In addition to raw pixel pushing, we've come to rely on a number of features to make our 3D games look their best. Antialiasing is perhaps the best-known trick. Depending on how high you set a 3D card's antialiasing levels (2X, 4X, and so on), you can eliminate in greater thoroughness the jagged-line effect you see on diagonal lines in 3D-rendered space. A newer feature is called high dynamic range lighting, or HDR lighting. This 3D effect pushes lights and darks to their limit, creating the appearance of convincing light blooms, shadowed objects that retain their surface details, and other effects. Both Nvidia's and ATI's cards support antialiasing and HDR lighting, but only ATI's Radeon cards currently do both at the same time. Missing out on one or the other isn't a game-stopping sacrifice, but for games that support both (the Elder Scrolls IV: Oblivion, for example), the combined effects look great, and it's a shame to have to miss out by opting for an Nvidia card.