Conclusions
I should start by saying that we've not been able to test many of the R500-series GPU architectures' new features as extensively as we usually would due to lack of time, including the chips' Avivo video and display engine and some facets of edge and texture antialiasing. We also left out a minor feature known as the Radeon X1300 Pro. We'll have to address those things at a later date, when time permits.

That said, we've learned quite a bit about ATI's new GPUs in the preceding pages. We should probably break things down into pieces in order to make sense of it all.

From a pure graphics technology standpoint, the Radeon X1000 series of graphics processors doesn't break new ground with bold innovations, but it does give ATI nearly every feature that the GeForce 7 series GPUs have had over the Radeon X800s. Not only that, but ATI has added a number of worthwhile capabilities, including multisampled antialiasing with high-dynamic-range color modes, "free" tone mapping via the Avivo display engine, and much finer-grained batch sizes for dynamic flow control in Shader Model 3.0. ATI has also caught up with NVIDIA on the internal chip architecture front by decoupling the computational units responsible for the various stages of the graphics pipeline from one another, allowing more flexibility for the development of adventurous variations on the core GPU architecture, like the RV530.

If the R520 architecture and derivatives have a weakness, it may be performance in current applications given the number of transistors. The R520 apparently requires more transistors for what's basically a 16-pipe design than NVIDIA's G70 does with 24 pixel shaders and texture units. ATI has made up the deficit with higher GPU and memory clock speeds, but that tradeoff leads to higher power consumption than G70, even though ATI's GPU is manufactured on a smaller fab process. Then again, the Radeon X1800 XT outperforms the GeForce 7800 GTX in many cases. That performance gap may grow if future applications begin making extensive use of shaders with flow control, where ATI's architecture is more efficient. However, I certainly wouldn't expect that to happen overnight, and it may not happen during the lifespan of G70, R520, and their offspring.

These considerations are less of a concern in the middle of the graphics market than they are at the very high end, where ATI has resorted to extreme clock speeds to counter NVIDIA's widest GPU architecture. Our measured power consumption under load on the Radeon X1800 XL system was within three watts of the GeForce 7800 GT-based system. That's hardly a reason to panic. Smart use of asymmetric GPU design, as in the RV530 (if that proves to be smart), may help ATI achieve higher performance with fewer transistors and smaller power envelopes in the future, as well.

ATI faced some daunting challenges with this new GPU generation, and they have largely succeeded in meeting them. If they deliver the products on schedule, ATI could lay claim to bragging rights for having been first to deliver a top-to-bottom range of next-gen GPUs on 90nm process technology. As for the cards as products, well, let's look at them one by one.

At the very high end of the market, the Radeon X1800 XT is indeed a worthy competitor for the GeForce 7800 GTX. In Direct3D games, the X1800 XT is usually faster than the 7800 GTX. Unfortunately, ATI's weak showing in OpenGL games keeps the X1800 XT from capturing the undisputed heavyweight title. I also have a few concerns about the likely extent of the Radeon X1800 XT's availability in the market, given its relatively high GPU clock speeds. We will have to wait and see about that.

There are also a number of GeForce 7800 GTX cards on the market now with higher clock speeds than the MSI cards we tested. I chose the MSI cards simply because I wanted a matched pair of cards for use in SLI, and I didn't have a pair of "overclocked in the box" cards on hand. NVIDIA's board partners have been pretty aggressive about ramping up the G70's clock speeds and standing behind those cards with lifetime warranties, and those cards might give the Radeon X1800 XT more of a run for its money in Direct3D apps—at the expense of higher power consumption, of course.

We may have a rematch between the Radeon X1800 XT 512MB and a new 512MB version of the GeForce 7800 GTX shortly, too, that could produce a clear champ.

The battle between the Radeon X1800 XL and the GeForce 7800 GT is close, but I'd have to give the edge to the 7800 GT. On balance, the 7800 GT is faster, though there are occasions, like in Far Cry and the F.E.A.R. demo, where the X1800 XL outruns even the GeForce 7800 GTX. Assuming the Radeon X1800 XL can soon hit the lower price points that some 7800 GT cards are hitting, it ought to be a very competitive product.

The Radeon X1600 XT confounds me. Admittedly, our test suite was best suited for high-end graphics cards, and the extensive use of antialiasing and anisotropic filtering probably hurt the X1600 XT's standing in our results. Still, this card lists for $249 and has 256MB of memory onboard, which is territory where I'd expect to be able to use high-quality edge and texture antialiasing in current games. Only in select cases can the Radeon X1600 XT keep pace with NVIDIA's like-priced offering, the GeForce 6800. I appreciate ATI's boldness in choosing an asymmetrical GPU design with the RV530; five vertex pipes and 12 pixel shaders at 590MHz aren't easily discounted. However, in light of the performance we've seen and the size of the chip, this feels more like a $179 product to me—more of a true GeForce 6600 GT competitor. The X1600 XT may age well as more shader-laden games take hold, but I wouldn't cough up $249 for one now when the GeForce 6800 can be had for less.