Quad SLI with 9800 GX2: Pushing a System to its Limit
by Derek Wilson on March 25, 2008 9:00 AM EST- Posted in
- GPUs
The Setup and The Test
We did have some issues again with this one. If you’ve already got one 9800 GX2 with the driver installed, uninstall the driver, reboot, power down, plug in the second card, boot, reboot, then install the driver. Trust me, it will save you a headache. It seems NVIDIA and AMD still need some time to sort out Vista and multi-GPU when adding a card or removing a card. We didn’t have the same problems we did with CrossFireX, but the potential is there to cause some frustration.
We also ran into a huge (in our opinion) bug that was very difficult to track down. The first two things we do when our graphics driver is installed is to disable vsync and disable image scaling to fit panel size. We run with no scaling at centered timings. This affords us the ability to see things at the same DPI across the board and it also gives us the ability to tell what resolution we are running by looking at the screen. This saves us a lot of trouble when things inevitably get mucked up for one reason or another. I also tend toward the obsessive / compulsive and if I can’t see it, I need to set the res like four times just to be sure.
In any case, 2x 9800 GX2 cards in Quad SLI will not run any games at less than panel resolution if scaling is disabled. You run the game and get a black screen. If you change resoluion in the game to something lower than panel res you get a black screen. Well, to be fair, it’s not just a black screen. It’s a hard lock. This needs to be fixed. It happens on both Skulltrail and 780i, so it’s not an isolated issue.
Also, NVIDIA decided to install a link to a trial version of Portal on the user's desktop when their driver is installed. I suppose a link to the site is better than bundling Earthsim, but not even asking if their customer wants more clutter on their desktop before putting it there is terribly inappropriate. I don’t care about bundling a trial, but please ask before you put something on my desktop.
The test system we used is the same as the one from the 9800 GX2 review, as are the driver revisions.
| Test Setup | |
| CPU | 2x Intel Core 2 Extreme
QX9775 @ 3.20GHz |
| Motherboard | Intel D5400XS (Skulltrail) |
| Video Cards | ATI Radeon HD 3870
x2 ATI Radeon HD 3870 NVIDIA GeForce 9600 GT 512MB NVIDIA GeForce 8800 GT 512MB NVIDIA GeForce 8800 Ultra NVIDIA GeForce 9800 GX2 |
| Video Drivers | Catalyst 8.3 ForceWare 174.53 |
| Hard Drive | Seagate 7200.9 120GB 8MB 7200RPM |
| RAM | 2xMicron 2GB FB-DIMM DDR2-8800 |
| Operating System | Windows Vista Ultimate
64-bit SP1 |
Thanks goes out to EVGA for supplying the two 9800 GX2 units for this review.
As for power consumption, here’s what we’ve got from these beasts.
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Lorne - Tuesday, March 25, 2008 - link
I dissagree, Its in every developers best intrest to flex there emuscles when they can, It keeps the compotition between them going and also keeps prices down and the next techno advances coming to us.What I do like in alot of articals like this one and few others Ive read is the idea of the 3 hardware giants almost putting there heads together to solve a common problem area.
I wanted to put a quote here about a mention of Crysis being a single thred program but couldnt find it again, Did I read this wrong or is it true that 7 cores generaly sat idle, That would be bad programming not a harware limitation, A spec of how CPU utilisasion would also be good in the testing of these game demo's
The other comment I wanted to bring up was that FBDDR is slower then UBDDR, This could be the limiting factor and along with the formentioned why the swap to the N780 setup did better.
DerekWilson - Thursday, March 27, 2008 - link
"I wanted to put a quote here about a mention of Crysis being a single thred program but couldnt find it again, Did I read this wrong or is it true that 7 cores generaly sat idle, That would be bad programming not a harware limitation, A spec of how CPU utilisasion would also be good in the testing of these game demo's "it's not bad programming really... there are some things you just CAN'T split up to run in multiple threads without adding more sync overhead than performance from parallelism.
In any case, I did a quick test here ---
Crysis seems to have 3 main gameplay threads that do most of the heavy lifting. One bounces around at some pretty high utilization.
The other 5 threads are sitting at between 10 and 20% utilization.
Overall during gameplay on skulltrail we see total cpu utilization (average of all cores) at between 20% and 30%.
Moving beyond 4 cores should (and does) have zero impact on crysis with this information.
Two cores would likely even provide enough power to get by as two of the 3 cores that were more than 20% active sat betwenen 30% and 50% utilization each. Taking these two threads, if they were to run on one core, you'd never see more than 80% utilization.
tviceman - Tuesday, March 25, 2008 - link
How many people own skull trail platforms and have dual 9800GX2's? Ten. There are ten people that have this setup. For everyone else, it's a pipe dream so far fetched I think I'd have better chances winning the local lottery than owning this kind of system.Seriously though, there are significantly more cons than pros when using skull trail to benchmark video card performance. The raw power of 8 CPU's is great in theory but it's not translating in real world gaming applications (in some cases it's hurting).
Video card reviews would be served better with the fastest quad core CPU available, accompanied with the highest performance motherboard out, and an excellent CPU cooler to allow for maximum overclock.
charlie brown - Wednesday, April 2, 2008 - link
lol i agree no one will be able to afford this type of setup and if they did it is a waste of money.I agree that anandtech should post realistic equipment aimed at the enthusiastic croud rather than the rich kid with skulltrail. Try a qx9650 and e8500 chips and see what happens with the benches.
Graphics drivers are not mature enough for the multi sli technology, and games are not mature enough for 4 cores - this review makes spending all that money look nothing but a waste of hard earned cash!!!
SniperWulf - Tuesday, March 25, 2008 - link
I wholeheartedly agree. Not only is it too expensive, but its not practical. What enthusiast you know will actually buy a setup like that? None I know, and prolly not any on the forums either.Sure, you want to test apples to apples... But the true apples to apples test is the hardware that people can get off newegg or zzf. 780i's and x38s with cheap but good DDR2 and DDR3 (well skip the cheap on DDR3 lol) and a nice penryn core cpu
legoman666 - Tuesday, March 25, 2008 - link
The reason they use skulltrail on all of the recent graphics card benchmarks is because it's the only chipset that supports SLI and Crossfire. It's the only way you'll see an apples to apples comparison. So stop your complaining.Inkjammer - Tuesday, March 25, 2008 - link
I agree on that. My E6600 w/9800 GX2 doesn't get near the performance Anandtech got in their review. In fact, the performance was still great, but really disappointing by comparison. Then I realized the benchmark was done with 6+ more cores than I have.The huge CPU power slightly skews realistic performance expectations on an otherwise high end PC. Great for showing card potential, not great for performance you can realistically expect.
DerekWilson - Tuesday, March 25, 2008 - link
My numbers do not change if I pull one processor.I tested that -- number of cores do not matter. Only speed of the cores.
tviceman - Tuesday, March 25, 2008 - link
Which was along the lines of the primary the point I was making. Why not just use the highest performance motherboard available and a single quad core processor overclocked like crazy? At least, in that regard, you're still using the best processor and best mobo out, which both can be had in a custom system for what the (almost) general masses can afford.I think there is a time and place for extreme high end reviews. But when extremely high end hardware is used in EVERY review, applicable performance expectations to the masses don't exist. I like your reviews; you're thorough you write well, it's just that reading these types of reviews consistently is more like listening to an extremely wealthy individual brag about all his toys. And by no means am I calling you a snob - hardware reviews are a part of your job as well as a priviledge. I will, never in the next few years, meet anyone with a system set up to be as expensive as what hardware reviewers regularly test with.
tviceman - Tuesday, March 25, 2008 - link
Sorry I used the word review in every single sentence. I was typing in a hurry and I didn't proof read.And to once again make it clear, you do a great job reviewing hardware and I enjoy all the article put out by everyone on anandtech. I just question the use of extreme high end hardware in EVERY review (like the 9600GT vs. 3870, is the skull trail necessary there?)