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ATI's Radeon X1950 XTX CrossFire: Quad SLI killer? August 28, 2006 Brandon Sandman Bell |
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Summary: Last week we took a look at the performance of ATI's Radeon X1950 XTX and found it to be a terrific performer. But what about X1950 XTX CrossFire? Can two Radeon X1950 XTX cards running in CrossFire mode actually outperform NVIDIA's vaunted Quad SLI technology? The answer is yes and no. For details on that topic, as well as ATI HDR+AA benchmarks in Oblivion, you won't want to miss today's article!
 Introduction | Page:: ( 1 / 18 ) |
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Today we’re taking a look at the Radeon X1950 XTX CrossFire Edition card, the companion card of the Radeon X1950 XTX we previewed last week. The X1950 XTX CrossFire shares the same clock speeds as the X1950 XTX, 650MHz core/1.0GHz memory (2.0GHz effective), and supports all the Radeon X1950 XTX’s new features, most notably HDCP support (via DVI) and the X1950 XTX’s new heat pipe cooling.
In comparison to previous CrossFire boards, ATI’s made no changes to the Radeon X1950 XTX CrossFire, the board relies on the same compositing engine first introduced with the Radeon X1800 XT CrossFire Edition and also uses the same dongle system ATI has used on previous CrossFire boards. In the case of the compositing engine, this is certainly a good thing, as the Xilinx FPGA at the heart of ATI’s compositing engine handles the blending used for CrossFire’s Super AA mode. With blending handled in hardware, enabling ATI’s Super AA modes with newer CrossFire cards comes at a significantly reduced performance hit.
In the past we’ve shown you how ATI’s Radeon X1900 CrossFire and X1800 XT CrossFire stack up against NVIDIA’s GeForce cards when the two are running their respective 8x, 14x, and 16xAA modes, finding that ATI’s cards deliver significantly greater performance.
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But how do a pair of Radeon X1950 XTX CrossFire cards perform in comparison to NVIDIA’s mighty GeForce 7950 GX2 Quad SLI? That’s precisely what we set out to test in today’s article.
| Test Systems | Page:: ( 2 / 18 ) |
System Setup
Intel Core 2 Extreme X6800
ASUS P5W DH Deluxe (for ATI systems)
ASUS P5N32-SLI SE Deluxe (for NVIDIA systems)
2GB Corsair TWIN2X2048-6400C4
ATI Radeon X1950 XTX 512MB
ATI Radeon X1900 XTX
Catalyst 6.8
BFG GeForce 7950 GX2
Driver version ForceWare 91.45
NVIDIA GeForce 7900 GTX
Driver version ForceWare 91.33
250GB Maxtor Hard Drive Maxline III SATA Hard Drive w/16MB Cache
Windows XP Professional SP2
DirectX 9.0c
Benchmarks
Half-Life 2 Lost Coast
Far Cry 1.33 (1.4 patch for ATI cards)
F.E.A.R. 1.07
Quake 4 1.2
Elder Scrolls IV: Oblivion
Battlefield 2 1.3
Call of Duty 2 1.2
A caveat
Before we get started, we should note one quick item: 4xAA testing. We’re going to exclude Quad SLI from most of these tests, as we’ve already shown you that the GeForce 7950 GX2 Quad SLI cards aren’t even capable of outperforming a GeForce 7900 GTX SLI config in most situations with 4xAA/16xAF, so we’re going to give ATI the edge here by default (with the exception of F.E.A.R. and Quake 4, two of the only applications that we test with which scale well under 4xAA for Quad SLI). We should also note that all NVIDIA cards are tested with the “High Quality” setting enabled in the NVIDIA control panel, the default setting is “Quality”. Also, all cards tested here are running with their respective adaptive AA and transparency AA modes turned on, with supersampling being used for all ATI and NVIDIA cards.
We attempted to test HDR+AA with Oblivion and a Chuck version of Catalyst 6.8 provided by ATI, but the X1950 XTX CrossFire card refused to work with AA enabled, crashing back to the desktop every time.
We’re going to be taking a look at the image quality delivered under the various AA and AF modes (as well as the optimizations in the control panel) in Part 2 of our Image Quality roundup (complete with more benchmarks), so be on the lookout for that article shortly.
| 3DMark 06 | Page:: ( 3 / 18 ) |
3DMark 06 – Direct3D
| HDR: HL2 Lost Coast | Page:: ( 4 / 18 ) |
Half-Life 2: Lost Coast – Direct3D
| Battlefield 2 | Page:: ( 5 / 18 ) |
Battlefield 2 – Direct3D
| Quake 4 | Page:: ( 6 / 18 ) |
Quake 4 – OpenGL
| F.E.A.R. Performance | Page:: ( 7 / 18 ) |
F.E.A.R. – Direct3D
| F.E.A.R. Performance 1600x1200 | ||
| Card | Min FPS | Max FPS |
| GeForce 7950 GX2 Quad | 56 | 315 |
| GeForce 7900 GTX SLI | 47 | 297 |
| Radeon X1900 XTX CrossFire | 30 | 231 |
| Radeon X1950 XTX CrossFire | 36 | 251 |
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| Oblivion Mountains HDR | Page:: ( 8 / 18 ) |
Oblivion – Direct3D
| Oblivion Performance 1600x1200x32 | ||
| Card | Min FPS | Max FPS |
| GeForce 7900 GTX SLI | 41 | 83 |
| Radeon X1950 XTX CrossFire | 54 | 83 |
| Radeon X1900 XTX CrossFire | 52 | 77 |
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| Oblivion Foliage HDR | Page:: ( 9 / 18 ) |
Oblivion – Direct3D
| Oblivion Performance 1600x1200x32 | ||
| Card | Min FPS | Max FPS |
| GeForce 7900 GTX SLI | 26 | 38 |
| Radeon X1950 XTX CrossFire | 49 | 64 |
| Radeon X1900 XTX CrossFire | 46 | 59 |
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| HDR+AA Oblivion | Page:: ( 10 / 18 ) |
Oblivion – Direct3D
| Oblivion Performance 1600x1200x32 | ||
| Card | Min FPS | Max FPS |
| Radeon X1950 XTX CrossFire | 30 | 62 |
| Radeon X1950 XTX | 17 | 46 |
| Radeon X1900 XTX CrossFire | 26 | 58 |
| Radeon X1900 XTX | 14 | 38 |
| ||
| HDR+AA Foliage | Page:: ( 11 / 18 ) |
Oblivion – Direct3D
| Oblivion Performance 1600x1200x32 | ||
| Card | Min FPS | Max FPS |
| Radeon X1950 XTX CrossFire | 24 | 29 |
| Radeon X1950 XTX | 13 | 15 |
| Radeon X1900 XTX CrossFire | 21 | 24 |
| Radeon X1900 XTX | 12 | 13 |
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| Call of Duty 2 | Page:: ( 12 / 18 ) |
Call of Duty 2 – Direct3D
| Super/SLI AA: HL2 Lost Coast | Page:: ( 13 / 18 ) |
Half-Life 2: Lost Coast – Direct3D
| Super/SLI AA: CoD 2 | Page:: ( 14 / 18 ) |
Call of Duty 2 – Direct3D
| Super/SLI AA: Quake 4 | Page:: ( 15 / 18 ) |
Quake 4 – OpenGL
| Super/SLI AA: F.E.A.R. | Page:: ( 16 / 18 ) |
F.E.A.R. – Direct3D
| F.E.A.R. Performance 1600x1200 | ||
| Card | Min FPS | Max FPS |
| GeForce 7950 GX2 Quad 4xAA | 56 | 315 |
| GeForce 7950 GX2 Quad 8xAA | 38 | 263 |
| GeForce 7950 GX2 Quad 16xAA | 20 | 146 |
| GeForce 7900 GTX SLI 4xAA | 47 | 297 |
| GeForce 7900 GTX SLI 8xAA | 25 | 165 |
| GeForce 7900 GTX SLI 16xAA | 11 | 153 |
| Radeon X1900 XTX CrossFire 4xAA | 30 | 231 |
| Radeon X1900 XTX CrossFire 8xAA | 21 | 114 |
| Radeon X1900 XTX CrossFire 14xAA | 15 | 98 |
| Radeon X1950 XTX CrossFire 4xAA | 36 | 251 |
| Radeon X1950 XTX CrossFire 8xAA | 24 | 131 |
| Radeon X1950 XTX CrossFire 14xAA | 16 | 108 |
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| Super/SLI AA: BF2 | Page:: ( 17 / 18 ) |
Battlefield 2 – Direct3D
| Conclusion | Page:: ( 18 / 18 ) |
With this in mind, how does the Radeon X1950 XTX CrossFire compare to Quad SLI? It depends on how you want to look at the results.
When the two cards are run under equal workloads, NVIDIA’s Quad SLI GeForce 7950 GX2 outperforms the Radeon X1950 XTX CrossFire setup. The actual amount varies from game-to-game, we saw the greatest margin of victory for the Quad SLI rig in Quake 4, at 2048x1536 the margin separating the GeForce 7950 GX2 Quad from the Radeon X1950 XTX CrossFire was 29%. We saw the narrowest margin in Call of Duty 2. Here the slimmest margin of victory for the Quad SLI config was 12% at 1600x1200, and the difference only opened up as great as 18% at 2048x1536. In the other apps we tested, the cards were separated anywhere from roughly 16% up to about 25%.
Despite the strength of ATI’s compositing engine, four G71 GPUs running in sync with each other is too much for the Radeon X1950 XTX CrossFire board to overcome, NVIDIA’s GeForce 7950 GX2 Quad SLI setup is the clear winner at 8xAA. But the tables quickly turn once you crank up the AA.
Once we turn up the AA levels to 14x for the ATI cards and 16x for the NVIDIA cards, the performance edge shifts dramatically in ATI’s favor. Here Call of Duty 2 favors the Radeon X1950 XTX CrossFire setup more so than any other game, with the X1950 CrossFire running 32% faster than the Quad SLI rig. We should note that the margins separating the two configs were tight in our Half-Life 2 Lost Coast and F.E.A.R. testing, with the difference ranging from anywhere between 4% (F.E.A.R. at 2048x1536, where just 1 FPS separated the two cards, well within the margin of error) to 9% (our 1920x1200 and 2048x1536 testing with HL2 Lost Coast). The margin separating the Quad SLI and CrossFire rigs was in the teens in Battlefield 2 and Quake 4. One other aspect we should note however is that the workload between the CrossFire setup isn’t even with the workload of Quad SLI, as ATI’s 14xAA mode uses 12x multisampling AA mixed with 2x supersampling AA, while the GeForce 7950 GX’s 16xAA mode uses NVIDIA’s 8xS mode, with each card running NVIDIA's 8xS mode with different sampling patterns.
Based on our 8xAA benchmark results (where both ATI and NVIDIA cards rely on 4x multisampling), you could assume that NVIDIA’s GeForce 7950 GX2 would perform better than Radeon X1950 XTX CrossFire if NVIDIA offered an equivalent 14xAA mode of their own, but as of right now they don’t. Perhaps seeing their flagship GeForce 7950 GX2 Quad SLI losing to the Radeon X1950 XTX CrossFire will motivate NVIDIA’s driver team to open up new AA modes besides the basic options available now, but perhaps they may not.
In terms of basic 4xAA/16xAF performance, the Radeon X1950 XTX CrossFire manages to outperform NVIDIA’s GeForce 7900 GTX SLI setup, with the Quad cards putting up impressive numbers in F.E.A.R. and Quake 4, one of the only apps that’s capable of taking advantage of Quad under 4xAA. We should also note that the Radeon X1950 XTX CrossFire combo managed to pull a little further away from X1900 XTX CrossFire in comparison to the single GPU benchmarks we reported last week. When confined to a single card setup, we often found the X1900 XTX finished just 3-6% behind the X1950 XTX, despite having significantly less memory bandwidth, but in our tests today with dual cards the X1950 XTX often outperforms the X1900 XTX by 6% or more, in fact with F.E.A.R. the difference was 10% or greater. So clearly the X1950 XTX scales better under dual-GPU configs.
That about does it for our first look into the Radeon X1950 XTX and X1950 XTX CrossFire. If ATI can deliver on their price and availability figures for the cards ($449 and 9/14 availability) they should prove to be pretty popular among ATI enthusiasts. We’d also like to see ATI offer CrossFire users the ability to create game profiles for specific games. Right now you really can’t tweak CrossFire support in the Catalyst driver, either the game works or it doesn’t. Starting with Catalyst 6.7 ATI offered the ability to force AFR mode by changing the Catalyst A.I. slider to “advanced”, but that’s about it, they still haven’t gone nearly as far as NVIDIA has in this regard, this is the one area where SLI is clearly ahead of CrossFire, SLI is also compatible with a wider variety of games. Fortunately, CrossFire compatibility is improving, and obviously if the game doesn’t scale you’ve always got the option of Super AA, it’s here where CrossFire certainly delivers…