ATI Technologies' counter-offensive:
RADEON X1800 (R520),
X1600 (RV530), and X1300 (RV515) Series
Part 4: Rendering Quality, New Anti-Aliasing and Anisotropic Filtering Modes
TABLE OF CONTENTS
- Part 1: Theory and architecture
- Part 2: Practical examination
- Part 3: Game test results (performance)
- Part 4: Render quality comparison in games
Conclusions on the rendering quality comparison results
Be warned that our conclusions are strictly preliminary: it's quite clear that the Radeon X1x00 series is quite "green" so far, in terms of drivers as well as application support. Many of the issues we have found today may be fixed in the nearest months.
ATI should do something with the shoddy program called Catalyst Control Center — the overwhelming majority of negative issues in the Radeon X1800 XT were caused by this clumsy, terribly slow, buggy, illogical, and inconvenient control panel. If ATI releases some CCC Lite to offer the same settings, which won't take up 50 MB of RAM, won't fall into comatose stupor at the sight of software firewall, won't refuse to apply settings with Fraps running, won't freeze for 20-30 seconds after you press the Apply button on a computer with Athlon 64 3700+ CPU... Hope we made ourselves clear.
Unfortunately, CCC has existed for over a year already practically without modifications, which is not particularly hopeful in prospects of fast remedy for this situation. For now we establish a fact that it's much more convenient to control GeForce settings via the standard control panel than to control Radeon settings via the monstrous CCC, drinking a cup of mint tea in pauses between key presses awaiting the results.
SM3 works fine in the RX1800, all SM3 applications start in SM3 modes. New Radeon cards are all right in this aspect.
But the new Radeon cards have troubles with FP16 rendering — the majority of games either ignore our attempts to activate HDR rendering on the Radeon X1800 XT, at least similar to that in the GF7800; or start glitching, demonstrating black screens and "sunny" horizontal stripes.
The problem will most likely be fixed with the release of new drivers and patches for corresponding games. As for now, we can only establish a fact that FP16 HDR rendering does not work on the Radeon X1x00.
Adaptive AA mode works exactly as it should. It's almost a complete match to Supersampling Transparency AA on the G70. G70's Multisampling Transparency AA mode is not implemented in the R520 (the problem may again be in "green" drivers).
The new algorithm of anisotropic filtering is practically identical in quality to the model anisotropy in the NV2x chips. But it also practically doesn't affect the performance — a pleasant feature in the new line of ATI video cards.
But the new algorithm demonstrates a weak effect in real applications and is almost no different from the old one. The most probable reason is the lack of flat large sloping surfaces in the latest games, which would show the new algorithm to the best advantage. But now any large flat surface is always covered with either trees, or grass, or waves — there are actually much fewer real applications for the new anisotropy algorithm in the R520 than we'd like to have.
If we compare the quality of Radeon X1800 XT and GeForce 7800 GTX directly, we are inclined to consider the rendering quality of these video cards to be very similar, sometimes even identical — you won't make a mistake by choosing any of them.
The GF7800 demonstrates objectively worse quality of anisotropic filtering with default driver settings. But you can repair it by moving a slider and losing maximum 10% fps.
What concerns antialiasing, the prize goes to Radeon, as the only card with absolutely playable 6x+AAA mode, which perfectly smoothes not only triangle edges, but also transparent textures. Let's hope that Adaptive AA will start working under OpenGL, as new drivers appear. The 8xS+TAA mode in GeForce cards offers similar quality to 6x+AAA, but it is much slower.
Remember, these are not our final conclusions. The Radeon X1x00 line will most likely recover from a larger part of its infant diseases in the nearest months. If we are lucky, it will also get rid of its crazy CCC.
Stay with us, read 3Digest — a lot of interesting awaits us in future :-)
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