Conclusions
AMD has made tremendous strides with this generation of GPUs. The Radeon HD 3870 delivers almost exactly the same performance as the Radeon HD 2900 XT, yet the chip is under half the size and brings an astounding near-100W reduction in power use while gaming. Since less power is expended as heat, the HD 3870 can be vastly quieter, as well. Honestly, I didn't expect these sorts of efficiency gains from what is essentially still an R600-derived design—and it certainly appears now that AMD overshot in a major way when it gave the 2900 XT a 512-bit memory interface. That error has been corrected, and R600's core architecture suddenly looks much nicer than it had before.

AMD needed every inch of that progress in order to come within shouting distance of the outstanding GeForce 8800 GT. Fortunately, they've done it, and the Radeon HD 3870 looks like a reasonable alternative, provided AMD can make good on its $219 price target. No, the HD 3870 isn't as fast as the GeForce 8800 GT, but we tested the latest games at very high resolutions and it still achieved some decent frame rates in today's games—except for, you know, Crysis, which bogs down any GPU. If you're using a display with a more common resolution like 1600x1200, 1680x1050, or 1920x1200, the HD 3870 will typically allow you to turn up the eye candy and still get fluid performance. Some folks will probably be willing to take that deal and pocket the difference in price versus the 8800 GT. I can't say I'd blame them.

And, as complex as these GPUs are, the issues really do boil down to price, performance, and adequacy at the end of the day. The DirectX 10 spec has firmed up the requirements for image quality, and partially as a result, the latest Radeons and GeForces produce very similar, great-looking output. Although I think AMD has something of an edge in terms of HD video playback filtering and noise reduction in some ways, even that is largely a wash. Most HD movies are going to look gorgeous on either card, regardless. I do plan to test HD video playback on these new cards soon, so we can get a closer look, though.

I'm not sure what to make of the Radeon HD 3850. The price is right, and it certainly delivers an awful lot of GPU power for the money. Yet the 256MB memory size in many "enthusiast value" graphics cards increasingly feels like a mismatch with the available processing power as GPU throughput increases. The HD 3850's memory size may not prevent folks from having a good experience in most of today's games, especially if they're playing at display resolutions of 1600x1200 or less. But some games have higher memory requirements than others, and such requirements are always growing as newer games arrive. Features like antialiasing and anisotropic filtering require additional memory, as well. Owners of the HD 3850 may have to turn down some settings and compromise on image quality in order to play some games smoothly, even when the GPU has power to spare.

The precise impact of that compromise is hard to gauge, but I can say with confidence that the HD 3850 is a poor choice for use in CrossFire configurations. Adding a second card can nearly double your effective GPU power, but it does nothing for your effective memory size, which remains the same as with one card. In fact, the overhead for coordinating with another GPU in CrossFire probably consumes some video memory, which may be why CrossFire was actually slower on the HD 3850 in some cases, yet faster on the 2900 XT. That makes an HD 3850 CrossFire rig a pretty extreme mismatch between GPU power and video RAM.

I should mention that budget-minded folks who like the idea of a GPU-RAM size mismatch will have another option soon in the form of the GeForce 8800 GT 256MB for between $179 and $199. It's no accident that range starts at the HD 3850's list price, of course, and given what we've seen today, the 8800 GT 256MB ought to be faster than the HD 3850. I'd really rather have either company's 512MB card, though, personally.

The next big question, I suppose, is how pricing and availability of 8800 GT and Radeon HD 3800-series graphics cards will play out over the next little while. I don't think there are any bad choices here, especially among the 512MB cards. AMD will need to maintain its price advantage, though, in order to offer as compelling a product as the 8800 GT.