ATI Radeon HD 3870 X2: 2 GPUs 1 Card, A Return to the High End
by Anand Lal Shimpi on January 28, 2008 12:00 AM EST- Posted in
- GPUs
Single-board CrossFire
The Radeon HD 3870 X2 features a single CrossFire connector at the top of the PCB, meaning you'll eventually be able to add a second card to it to enable 3X or 4X CrossFire modes (depending on whether you add another 3870 X2 or just a single 3870).
Unfortunately driver support for the ATI CrossFireX technology isn't quite there yet, although AMD tells us to expect something in the March timeframe. Given that CeBIT is at the beginning of March we're guessing we'll see it at the show.
As we alluded to earlier, the fact that the 3870 X2 features two GPUs on a single board means that it doesn't rely on chipset support to enable its multi-GPU functionality: it'll work in any motherboard that would support a standard 3870.
Driver support is also seamless; you don't have to enable CrossFire or fiddle with any settings, the card just works. AMD's Catalyst drivers attempt to force an Alternate Frame Render (AFR) mode whenever possible, but be warned that if there are issues with the 3870 X2's multi-GPU rendering modes and a game you may only get single-GPU performance until AMD can fix the problem. In our testing we didn't encounter any such issues but as new games and OS revisions come out, as we saw with the GeForce 7950 GX2, there's always the chance.
AMD insists that by releasing a multi-GPU card it will encourage developers to take CrossFire more seriously. It is also committed to releasing future single-card, multi-GPU solutions but we'll just have to wait and see how true that is.
Last Minute Driver Drop: Competitive Crysis Performance
Today's launch was actually supposed to happen last week, on January 23rd. At the last minute we got an email from AMD stating that the embargo on 3870 X2 reviews had been pushed back to the 28th and we'd receive more information soon enough.
The reason for the delay was that over the weekend, before the launch on the 23rd, AMD was able to fix a number of driver issues that significantly impacted performance with the 3870 X2. The laundry list of fixes are as follows:
• Company of Heroes DX10 – AA now working on R680. Up to 70% faster at 2560x1600 4xAA
• Crysis DX10 – Improves up to ~60% on R680 and up to ~9% on RV670 on Island GPU test up to 1920x1200.
• Lost Planet DX10 – 16xAF scores on R680 improved ~20% and more. AF scores were horribly low before and should have been very close to no AF scores
• Oblivion – fixed random texture flashing
• COJ – no longer randomly goes to blackscreen after the DX10 benchmark run
• World in Conflict - 2560x1600x32 0xAA 16xAF quality=high we get 77% increase
• Fixed random WIC random crashing to desktop
• Fixed CF scaling for Colin McRae Dirt, Tiger Woods 08, and Blazing Angels2
• Fixed WIC DX9 having smearable text
With a list like that, we can understand why AMD pushed the NDA back - but most importantly, the Radeon HD 3870 X2 went from not scaling at all in Crysis to actually being competitive.
The Radeon 3800 series has always lagged behind NVIDIA when it came to performance under Crysis, and with the old driver Crysis was a black eye on an otherwise healthy track record for the 3870 X2. The new driver improved performance in Crysis by around 44 - 54% at high quality defaults depending on resolution. The driver update doesn't make Crysis any more playable at very high detail settings, but it makes the X2's launch a lot smoother than it would've been.
According to AMD, the fix in the driver that so positively impacted Crysis performance had to do with the resource management code. Apparently some overhead in the Vista memory manager had to be compensated for, and without the fix AMD was seeing quite poor scaling going to the 3870 X2.
The Test
| Test Setup | |
| CPU | Intel Core 2 Extreme QX9650 @ 3.00GHz |
| Motherboard | EVGA nForce 780i SLI Power Measurements done on ASUS P5E3 Deluxe |
| Video Cards | ATI Radeon HD 3870 X2 ATI Radeon HD 3870 NVIDIA GeForce 8800 GTX NVIDIA GeForce 8800 GTS 512 NVIDIA GeForce 8800 GT (512MB) |
| Video Drivers | ATI: 8-451-2-080123a NVIDIA: 169.28 |
| Hard Drive | Seagate 7200.9 300GB 8MB 7200RPM |
| RAM | 4x1GB Corsair XMS2 DDR2-800 4-4-4-12 |
| Operating System | Windows Vista Ultimate 32-bit |
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Blacklash - Wednesday, January 30, 2008 - link
I'd like to see a round up of ATi and nVidia's current mid to high range. Test them in games that allow 8xAA. I am hearing around in quite a few places ATi cards catch up or pass nVidia when you move from 4x to 8xAA. I'd love to see Anand prove this or debunk it.Giacomo - Tuesday, January 29, 2008 - link
I have to admit, even being a fan of nVIDIA, that I fell in love with this card. I like it in almost every aspect, I'm astonished by its combination of complexity and smooth working. Well: almost smooth, due to beta drivers. And this is an element of bigger interest too: there's even a bigger distance to put between itself and the rivals, when mature drivers are released.That said... I'm designing the last points of my new machine, I was ready to go with a 8800GTS 512MB, but suddenly stopped to look at this one... And I think I'll go with it.
But... On which motherboard? These are the thoughts I'd like to share with you, I ask you: did you notice that Anandtech ones are among the best results in the various X2 reviews online? And did you notice they're obtained on a 780i platform?
Initially, the most obvious idea was to buy this card together with an Asus Rampage Formula, so nicely reviewed on these pages. But now, looking at the system used for this review, the question: wouldn't my dear old desired eVGA 780i SLI an even better board for the new system, for this 3870 X2?
Don't need crossfire nor SLI, really.
Reviewer's opinion would be very appreciated too, of course, being the one who planned this "curious" match.
Giacomo
XrayDoc - Tuesday, January 29, 2008 - link
Does anyone know if the Intel X48 chipset will allow two of these cards to run in CrossfireX mode, or will you have to purchase an AMD chipset motherboard?karthikrg - Monday, January 28, 2008 - link
This seems to be a stopgap solution though its heartening to see AMD/ATI having the faster single card solution now (albeit multi-GPU). With the Nvidia 9800GX2 due soon, the race is sure to get interesting. Hope AMD has something up its sleeves with the R700FullHiSpeed - Monday, January 28, 2008 - link
This has nothing to do with graphics, but that PLX PEX8547 in the picture is a bridge, not a switch. Unfortunately, PLX doesn't make a Gen 2 PCIE bridge or switch. One would imagine that two GPU's on one board would benefit from the increased bandwidth of Gen 2. The PLX bridge/switch web page says the switches (and not the bridges) give "Low Latency Transfers" and "True Peer-to-Peer Data Transfers", both of which are probably important to this parallel processing application. This could explain why "the HD 3870 X2 is systematically 5% faster on average than the CrossFire solution" (nach Tom) in spite of the 16 lane Gen 1 bottleneck to the north bridge.Slaimus - Monday, January 28, 2008 - link
I am still confused by the way AMD/ATI is allocating RV670 chips. If you check on newegg, there are well over 100 Sapphire 3870X2s in stock, but the Sapphire 3870 is still out of stock.The same thing was happening during the initial 3870/3850 launch, where way too many of the 3850 were produced compared to the 3870. Also, none of the 3850s were of the 512MB type.
AMD should be filling the 3870 demand with the RV670 chips first, since it is probably the most profitable and most reasonable product.
phaxmohdem - Monday, January 28, 2008 - link
All I can think of is 2 GPU's 1 Cup :Sflat6 - Monday, January 28, 2008 - link
The article says: "the performance is indeed higher than any single-card NVIDIA solution out today", but they didn't test an 8800 Ultra. In some cases the card was barely beating the 8800 GTX. How would it stack up against an Ultra? I understand that maybe they didn't compare against an 8800 Ultra because of the price difference, but the reviewer was all excited about AMD/ATI's return to the high-end; at the high-end, cost is no object. And why two 8800 GTs? If this is the high-end, why choose mid-price cards for SLI? Why not use two Ultras?I'm not saying a single Ultra would have trounced this card, only that I would have liked to see the comparison. I do think, however, that if they'd gone truly high-end on the SLI side, two Ultras might have killed it.
strikeback03 - Monday, January 28, 2008 - link
http://www.anandtech.com/video/showdoc.aspx?i=3175...">http://www.anandtech.com/video/showdoc.aspx?i=3175...their previous testing showed the ultra as being similar in performance to the 8800 GTS 512 in most tests. So an Ultra (or 2 of them in SLI) might have done better in the AA tests, but not much else it would seem.
flat6 - Monday, January 28, 2008 - link
Thanks, I just read it. Good grief. I didn't realize the GTS 512 was that fast. Point taken.