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HDR+AA In Action with ATI's Radeon X1800/X1900s July 11, 2006 |
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Summary: One feature ATI's latest Radeon X1K cards have touted for some time is their ability to support HDR lighting with AA for improved visuals, but up to this point there's been little info out there about the topic. In this article we explore the performance of ATI's latest Radeon X1800 and X1900 cards (including the more affordable X1800 GTO and X1900 GT) with HDR+AA in Far Cry and Oblivion. Are these cards capable of delivering HDR+AA with playable frame rates? Find out in today's article!
 Introduction | Page:: ( 1 / 9 ) |
In that article we found that ATI’s Radeon X1800 XT was able to scale to very high AA modes with a surprisingly small performance hit thanks to ATI’s revamped compositing engine introduced in the Radeon X1800 CrossFire card. 8xAA was practically free, while the X1800 CrossFire setup was delivering pretty good performance at high resolutions even once 14xAA was enabled. This continued to be the case for the Radeon X1900 CrossFire as well.
But the one topic we hadn’t discussed at length (that you continued to remind us about in the comments) is ATI’s unique ability to support anti-aliasing with high dynamic range lighting (HDR), a feature found on all of their X1K cards. Only ATI’s Radeon X1K cards are capable of pulling off this feat.
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It’s important to note that when we refer to HDR+AA we’re talking about games that utilize floating-point values to generate their HDR lighting effects, these games include titles such as Far Cry, Splinter Cell: Chaos Theory, and Oblivion. Valve managed to integrate HDR support into their Half-Life 2 engine, but this utilizes your graphics card’s pixel shaders to produce HDR. This is why older graphics cards that technically didn’t support HDR can still run these effects in Half-Life 2 and HL2 Lost Coast.
By combining AA with HDR gamers can still get the razor sharp edges provided by MSAA with the environmental effects of HDR. Tomorrow’s games (including Epic’s upcoming shooter Unreal Tournament 2007) will increasingly take advantage of HDR lighting, so ATI fans have made the argument that this is one area where ATI’s Radeon X1K cards are more future-proof than NVIDIA’s GeForce 7. Up to this point however the argument has been tough to prove, as most online reviews have skipped over the topic.
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You see, HDR lighting comes with a significant performance hit even with today’s fastest graphics cards. As a result, most reviewers and end users have just assumed that combining one performance-sapping feature (HDR) with another (AA) would result in sluggish frame rates. As we’re about to show you today however, apparently that isn’t the case, as ATI’s latest X1K cards are capable of delivering very good frame rates in games like Oblivion and Far Cry, even once the game’s eye candy settings are cranked up and HDR+AA is enabled!
| System setup | Page:: ( 2 / 9 ) |
AMD Athlon 64 FX-62
MSI K9A Platinum (ATI CrossFire Xpress 3200)
ATI Radeon X1900 XTX
ATI Radeon X1900 XT
ATI Radeon X1800 GTO
ATI Radeon X1800 XT 512MB
Sapphire Radeon X1900 GT
Chuck Patch based on Catalyst 6.6 codebase
Western Digital Raptor 75GB
Windows XP Professional SP1
DirectX 9.0c
Benchmarks
Far Cry 1.4 Highest Quality Settings
Oblivion Highest Quality Settings
| Far Cry | Page:: ( 3 / 9 ) |
Far Cry – Direct3D
| Far Cry Performance 1280x1024 | ||
| Card | Min FPS | Max FPS |
| Radeon X1900 XTX | 68.7 | 108.8 |
| Radeon X1900 XT | 65.3 | 103.9 |
| Radeon X1800 XT 512MB | 55.1 | 78.1 |
| Radeon X1800 GTO | 33.6 | 48.7 |
| Radeon X1900 GT | 49.2 | 74 |
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| Far Cry HDR 2xAA/8xAF | Page:: ( 4 / 9 ) |
Far Cry – Direct3D
| Far Cry Performance 1280x1024 | ||
| Card | Min FPS | Max FPS |
| Radeon X1900 XTX | 63.9 | 103.6 |
| Radeon X1900 XT | 62.2 | 99.3 |
| Radeon X1800 XT 512MB | 52.1 | 75.8 |
| Radeon X1800 GTO | 31.8 | 47.5 |
| Radeon X1900 GT | 44.2 | 70.1 |
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| Oblivion HDR Outdoors | Page:: ( 5 / 9 ) |
Oblivion – Direct3D
| Oblivion Performance 1600x1200x32 | ||
| Card | Min FPS | Max FPS |
| Radeon X1900 XTX | 37 | 59 |
| Radeon X1900 XT | 36 | 56 |
| Radeon X1800 XT 512MB | 30 | 46 |
| Radeon X1800 GTO | 20 | 30 |
| Radeon X1900 GT | 26 | 43 |
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| Oblivion HDR 2xAA/8xAF Outdoors | Page:: ( 6 / 9 ) |
Oblivion – Direct3D
| Oblivion Performance 1600x1200x32 | ||
| Card | Min FPS | Max FPS |
| Radeon X1900 XTX | 29 | 46 |
| Radeon X1900 XT | 27 | 45 |
| Radeon X1800 XT 512MB | 26 | 40 |
| Radeon X1800 GTO | 17 | 26 |
| Radeon X1900 GT | 20 | 32 |
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| Oblivion HDR Foliage | Page:: ( 7 / 9 ) |
Oblivion – Direct3D
| Oblivion Performance 1280x1024x32 | ||
| Card | Min FPS | Max FPS |
| Radeon X1900 XTX | 35 | 43 |
| Radeon X1900 XT | 33 | 42 |
| Radeon X1800 XT 512MB | 29 | 38 |
| Radeon X1800 GTO | 20 | 26 |
| Radeon X1900 GT | 26 | 32 |
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| Oblivion HDR Foliage 2xAA/8xAF | Page:: ( 8 / 9 ) |
Oblivion – Direct3D
| Oblivion Performance 1280x1024x32 | ||
| Card | Min FPS | Max FPS |
| Radeon X1900 XTX | 29 | 37 |
| Radeon X1900 XT | 27 | 36 |
| Radeon X1800 XT 512MB | 26 | 33 |
| Radeon X1800 GTO | 17 | 23 |
| Radeon X1900 GT | 20 | 26 |
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| Conclusion | Page:: ( 9 / 9 ) |
Until today that is.
Adding 2xAA/8xAF to Far Cry running with HDR had very little effect on the Radeon cards relatively speaking. At 1600x1200 the Radeon X1900 XTX’s performance drops by just 2 fps, or a little over 4%, while the X1800 XT 512MB sees an even slimmer 2% drop off. Even the slower Radeon X1800 GTO and X1900 GT cards see only slight declines once AA is added on top of HDR in Far Cry.
Under the greater demands of Oblivion, the margins are definitely greater, but we still saw manageable frame rates; adding AA to HDR actually comes free at 1024x768 for all cards except the Radeon X1800 GTO, and keep in mind that we could easily turn down the graphics settings a little for even better performance. In our outdoors testing the Radeon X1900 XTX saw a performance dropoff of nearly 30% while the Radeon X1800 XT took at performance hit of 21% once HDR+AA was enabled. Similarly, the Radeon X1900 GT took a greater hit than the GTO.
This is probably because the GPU on the older R520 cards is already pretty bottlenecked once HDR is running in Oblivion, once AA is added, the GPU can’t bottom out much further. In the case of the R580-based cards, they’re not quite as overtaxed with just HDR running, so once HDR+AA is enabled you see performance decline significantly.
The differences between running with HDR and HDR+AA aren’t quite as significant in foliage testing simply because the foliage area is more stressful on the graphics card than the outdoors area.
Looking over the results, HDR+AA is certainly a lot more feasible on ATI’s Radeon X1K cards than we initially thought. Getting playable frame rates with HDR+AA shouldn’t be too hard as long as you keep the eye candy in check, and with older games like Far Cry you should be able to turn it all on while also running HDR+AA without any problems.
Now if we can just see what kind of performance we can expect from Crysis and Unreal Tournament 2007 once HDR+AA is turned on. Unfortunately we’ll all have to wait a little longer to see those results…