High Dynamic Range (HDR) Rendering
With SM 3.0 adoption, the Radeon X1K series are the first Radeon to directly support the preferred HDR SM 3.0 method used in games like Farcry and Splinter Cell Chaos Theory. However, unlike the GeForce 7 series, the Radeon X1K can still run with AA enabled when a game (or an application) make use of HDR. Let's take a look at Splinter Cell Chaos Theory first. The first screenshot is without HDR and the second one is with HDR. The third screenshot from the GeForce 7 is with HDR enabled, but tone mapping disabled.Radeon X1900
GeForce 7
Even without HDR, you can already see there are some differences between the X1900 and GeForce 7 shots, though not by much. The far side of the room (on the right) received more light on the GeForce 7 than on the Radeon X1900. You can also see some differences on the light bulb. Everything else is similar if not the same. With HDR enabled, the differences are more noticeable. In the GeForce 7 screenshot, the room is more lit than on the Radeon X1900. You'll can also see some differences on the light bulb. It is only when we turn off tone mapping on the GeForce 7 do get pretty much the same picture from both cards. So, is ATI 'skipping' a step here? We're not sure, but we decided to perform testing on the GeForce 7 both with and without tone mapping enabled.
Radeon X1900
GeForce 7
With the latest patch, you can enable both HDR and AA on the Radeon X1K series in Serious Sam II. Unlike Splinter Cell Chaos Theory, we can see virtually no difference between HDR on the Radeon X1900 and GeForce 7 series. The detail in the dirt path and clouds are present on both, as also the lens flare on the water fall (which the non HDR image lack).
It boils down to this. ATI's adaptive antialiasing is somewhat a mixed bag. In Performance mode, the image quality it offers is better than NVIDIA under the same setting. However, this is not the preferred mode of use. In Quality mode, which corresponds to supersampling on the GeForce 7 series, the Radeon adaptive antialiasing is not as effective. It only works well on objects that are near to the camera. There's still very noticeable aliasing (more so in motion) on faraway objects with transparent textures. Gamers looking for the best image quality in games with transparent textures, should be more happy with the GeForce 7 than the Radeon X1900.
While this may seem like a big deal, it's really not. Not all games or all game levels / maps utilize transparent textures. Even those who do will not always work with both ATI's adaptive antialiasing and NVIDIA's transparency antialiasing. NVIDIA is again the better card here - its 8xS can be used in such games. We haven't looked (yet) at the X1900 performance with adaptive antialiasing, but we already seen what the GeForce 7 can do. The performance penalty can be very high, higher than just applying AA alone and that's a lot considering the performance penalty of antialiasing on the GeForce 7 series. In some cases, you'll have to drop the number of samples to 2x to maintain playable frame rates. Or maybe buy another card to run the game under SLI.
Although the GeForce 7 offer the better image quality (transparent textures wise), transparency antialiasing on both cards is not really a feature worth buying for. Look at the options. A card that looks good but ran slowly or one that's not good but is possibly faster. This matter is very subjective, but that sentence is pretty much our view on the subject.
HDR is different. Quality wise, image quality from both cards is pretty much similar and comparable to each other. Theoretically, ATI have the upper hand here with the Radeon X1K supporting HDR with AA. Keep in mind though, current games supporting HDR must first be patched to enable HDR with AA. Future games making use of HDR should come with HDR and AA support out of the box. In this regard, HDR is more important than transparency antialiasing in performance evaluations. It's also easier since we can actually perform an apples to apples comparison. For this article, we decided to include benchmark results both with just HDR and HDR plus AA and AF. Just keep in mind that you should only compare the HDR only scores between the cards, since the GeForce 7 series don't support HDR and AA.
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