AMD's CrossFireX: Tri & Quad GPU Preview
by Anand Lal Shimpi on February 21, 2008 3:00 AM EST- Posted in
- GPUs
The Test
| Test Setup | |
| CPU | AMD Phenom @ 2.6GHz |
| Motherboard | MSI K9A2 Platinum |
| Video Cards | ATI Radeon HD 3870 X2 ATI Radeon HD 3870 |
| Video Drivers | Catalyst 8.1 (Modified for CrossFireX Support) |
| Hard Drive | Seagate 7200.9 300GB 8MB 7200RPM |
| RAM | 2x1GB Corsair XMS2 DDR2-800 4-4-4-12 |
| Operating System | Windows Vista Ultimate 64-bit |
We ran the following games in their corresponding quality settings:
| Game | Resolution | AA | AF | Detail Settings |
| Half Life 2: Episode Two | 2560 x 1600 | 8X | 16X | Highest in-game |
| Unreal Tournament 3 | 2560 x 1600 | 0X | 16X | Highest in-game |
| Bioshock | 2560 x 1600 | 0X | 1X | Highest in-game |
| Call of Duty 4 | 2560 x 1600 | 4X | 16X | Highest in-game |
| Crysis | 1920 x 1200 | 0X | 1X |
High Quality defaults |
The graph below shows the performance levels you can get from a single GPU all the way up to four:
Obviously the biggest jump comes from one to two GPUs, but we still see some reasonable gains going from two to three. The value of a fourth GPU is simply nonexistent in most of the cases.
| Number of GPUs | HL2 | UT3 | Bioshock | CoD4 | Crysis |
| 1 x Radeon HD 3870 | 39.3 | 46.7 | 36.9 | 25.3 | 14.0 |
| 2 x Radeon HD 3870 (1 X2) | 71.9 | 84.1 | 63.2 | 50.0 | 26.2 |
| 3 x Radeon HD 3870 (2 X2 + 1) | 93.3 | 112.7 | 86.7 | 72.2 | 26.4 |
| 4 x Radeon HD 3870 (2 X2) | 102.2 | 114.6 | 92.5 | 93.2 | 27.7 |
Let's put some percentages with the graph above to put things into perspective:
| Configuration | HL2 | UT3 | Bioshock | CoD4 | Crysis |
| 2-way CF Improvement over 1 card | 83% | 80% | 71% | 98% | 87% |
| 3-way CF improvement over 2 cards | 30% | 34% | 37% | 44% | 0% |
| 4-way CF improvement over 3 cards | 10% | 3% | 7% | 29% | 4% |
| 4-way CF improvement over 1 card | 160% | 150% | 151% | 268% | 98% |
The move from one to two cards generally yields a healthy performance improvement, but the gains taper off as we look at the performance added by a third GPU. Call of Duty 4 is the only game that shows solid gains with 4 GPUs (29% over a 3-GPU configuration), the rest of the titles show mostly single-digit percentage improvements. Once again we see that Crysis simply needs new, faster GPU architectures - four GPUs does absolutely nothing for this game.
Remember our 3-way SLI review from earlier in the year? Although the test systems were very different, the GPU-bound scaling should be comparable (if anything, NVIDIA should have the advantage of being run on an Intel system). Here's a quick look back at some of the comparable benchmarks:
| Configuration | UT3 | CoD4 |
| 2-way SLI Improvement over 1 card | 84% | 90% |
| 3-way SLI improvement over 2 cards | 20% | 28% |
| 3-way SLI improvement over 1 card | 121% | 143% |
Single to dual GPU scaling is similar with SLI as CrossFire, but the 2-way to 3-way gain is better on CrossFireX. NVIDIA's quad-SLI is not yet available so we're not sure how the 4-way scaling will compare, but so far it seems like CrossFireX is doing quite well in the pure numbers game.
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Spacecomber - Friday, February 22, 2008 - link
Having recently read the preview of the 9600GT at Anandtech, one of the things that stood out from that article was how SLI seemed to do better than Crossfire on the games that were tested. Crysis was the only game that was used in both this article and that one, and 3850's were run in Crossfire for the earlier article, not 3870's. Nevertheless, it looks like Crossfire performance gains going from 1 to 2 ATI cards is now on a par (with the new AMD/ATI drivers) with going from 1 to 2 Nvidia cards.Perhaps this will prove to be the reason for AMD/ATI selecting the tests they did in this preview. CrossfireX does about as well SLI on these particular games?
(Though we'll not see the results, we know that Derek is trying these new ATI drivers out on his Skulltrail system, if it's possible. ;-) )
Zoomer - Thursday, February 21, 2008 - link
Are you allowed to only test these games, or allowed to publish and talk about these games only?I don't see how ATi can enforce such a requirement. *cough* ghost *cough*
Wirmish - Thursday, February 21, 2008 - link
PC Perspective also test the beta-CrossFire-X.Their system is identical, except for the hard disk.
http://www.pcper.com/article.php?aid=523&type=...">http://www.pcper.com/article.php?aid=523&type=...
RÉSULTS:
Bioshock
Anand (0xAA/0xAF) -> 2=63, 3=87, 4=93
PCPer (0xAA/8xAF) -> 2=65, 3=84, 4=92
Call of Duty 4
Anand (4xAA/16xAF) -> 2=50, 3=72, 4=93
PCPer (4xAA/ 8xAF) -> 2=43, 3=56, 4=64
Unreal Tournament 3
Anand (0xAA/16xAF) -> 2=84, 3=113, 4=115
PCPer (0xAA/ 8xAF) -> 2=58, 3=54, 4=58
How do you explain these results ?
POWER CONSUMPTION - ENTIRE SYSTEM
Anand (Bioshock) -> 2=361W, 3=406W, 4=538W
PCPer (CoD 4) ----> 2=407W, 3=527W, 4=663W
Why didn't you choose the hungriest game to calculate the consumption of the system ?
Paracelsus - Thursday, February 21, 2008 - link
You've listed the 4-way CF over 1 card gain as 268%.It should be 368%. (95.2/25.3 = 3.68)
The numbers are confusing, comparing 3-way to 2-way etc. Why do that, makes more sense to compare 3-way to 1-way. Then it's easy to compare to the perfect scaling of 200, 300, 400%.
mechwarrior1989 - Thursday, February 21, 2008 - link
I got confused by it to but the Test Bench isn't what they listed on the page. Either that's a Typo or that's just supposed to refer to the Nvidia Benchmark that they did with the Tri-SLIkalrith - Thursday, February 21, 2008 - link
Yeah, it looks like they entered the test setup from the Nvidia article rather than the one used in this article. It would make sense if they entered both test setups but not to completely exclude the AMD setup used for most of the tests.Anand Lal Shimpi - Thursday, February 21, 2008 - link
Woops :) Fixed :)Take care,
Anand
Arbie - Thursday, February 21, 2008 - link
Good catch for Anandtech! AMD told you it was a Phenom board but you saw it was really a QX9650. The company must be in dire straits to try a trick like that. Sad.donkeycrock - Thursday, February 21, 2008 - link
The graph is the best and most effective one i've seen in anybody's review in a long time. cheers and well donebrunis - Thursday, February 21, 2008 - link
Hi, alot of people are still playing WoW, me included. I just bought the Samsung 245B, a wide 24" screen. I'd love to see a cpu+gpu update for the wow guide. If i should invest in an extra 8800GTS or a new Core2 or AMD Phenom cpu.
regards,
Brunis