What you make of the GeForce GTX 280 may hinge on where you come down on the multi-GPU question. Clearly, the GTX 280 is far and away the new single-GPU performance champ, and Nvidia has done it again by nearly doubling the resources of the G80. Its performance is strongest, relatively speaking, at high resolutions where current solutions suffer most, surely in part because of its true 1GB memory size. And one can't help but like the legion of tweaks and incremental enhancements Nvidia has made to an already familiar and successful basic GPU architecture, from better tuning of the shader cores to the precipitous reduction in idle power draw.
All other things being equal, I'd rather have a big single-GPU card like the GTX 280 than a dual-chip special like the Radeon HD 3870 X2 or the GeForce 9800 GX2 any day. Multi-GPU setups are fragile, and in some games, their performance simply doesn't scale very well. Also, Nvidia's support for multiple monitors in SLI and GX2 solutions is pretty dreadful.
The trouble is, things are pretty decidedly not equal. More often than not, the GeForce 9800 GX2 is faster than the GTX 280, and the GX2 is currently selling for as little as 470 bucks, American money. Compared to that, the GTX 280's asking price of $649 seems mighty steep. Even the GTX 260 at $399 feels expensive in light of the alternativesdual GeForce 8800 GTs in SLI, for instanceunless you're committed to the single-GPU path.
Another problem with cards like the 9800 GX2 is simply that they've shown us that there's more performance to be had in today's games than what the GTX 260 and 280 can offer. One can't escape the impression, seeing the benchmark results, that the GT200's performance could be higher. Yet many of the changes Nvidia has introduced in this new GPU fall decidedly under the rubric of future-proofing. We're unlikely to see games push the limits of this shader core for some time to come, for example. I went back and looked, and it turns out that when the GeForce 8800 GTX debuted, it was often slower than two GeForce 7900 GTX cards in SLI. No one cared much at the time because the G80 brought with it a whole boatload of new capabilities. One can't exactly say the same for the GT200, but then again, things like a double-size register file for more complex shaders or faster stream-out for geometry shaders may end up being fairly consequential in the long run. It's just terribly difficult to judge these things right now, when cheaper multi-GPU alternatives will run today's games faster.
And then there's the fact that AMD has committed itself to the multi-GPU path entirely for the high end. I can't decide whether that legitimizes the approach or makes Nvidia the winner by default. Probably, it's a little of both, although I dunno how that works. The folks at AMD are already talking big about the performance of RV700, their next-generation dual-GPU video card, though. We'll have to wait and see how these things play out.
Whatever happens there, Nvidia has opened up new selling points for its GPUs with CUDA and the apparent blossoming of a nascent GPU-compute ecosystem. Perks like PhysX acceleration and speed-of-light Photoshop work may make a fast GPU indispensable one day, and if that happens, the GT200 GPU will be ready to take full advantage.