low SLI performance

[brunch]

Hi! I posted here a long time ago when I first built my PC, and you guys were a great help! Now I'm hoping someone out there can help me with this problem that's plagued me ever since I finally got my compy working.

First, my specs:
Enermax Noisetaker 600W
MSI P4N Diamond
4x512MB Corsair RAM
Western Digital Raptor and Caviar
2xBFG GeForce 7800 GTX OC
Windows XP Pro SP2
P4 3.2 GHz

I've tried BFG tech support and Nvidia's SLI forum, to no avail. See, my SLI performance is the same as my single-card performance. My SLI benchmark in 3dmark05 was 8100 with the 81.95 drivers, and 6500 with the dhzeropoint 0.8195 dirvers, even though performance obviously increased with the modified drivers. Some games such as FEAR and B&W2 run equally slow with SLI on or off. I've tested my video cards individually with with the other removed, and they work fine. BFG phone tech support told me to install a nonexistant driver, so I tried every compatible driver. No effect. Then they told me to reformat my Raptor to get rid of Windows x64. Nothing. They said to replace my PSU (formerly an Antec 500W) and that didn't fix the problem. Finally, a tech support guy told me I shouldn't expect improved performance in SLI in games that weren't made for it, and that my score of 8100 was normal. I tried to email tech support but my email failed to make it through, so I went on Nvidia's SLI forum. Two other people had the same problem, one with an AMD build, and no one had a clue how to fix it. So I came here.

Any help at all would be appreciated, even if it doesn't help. Actually, I'm hoping an awesome PCI-e sound card comes out so I can get rid of one of my video cards with a clean conscience. But of course I would prefer to have the high-end gaming system I paid for.

Thanks in advance!
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[brunch]

bump

[giantkoreandorq]

I actually think those test results might be normal. When comparing your computer specs to the one they use in Tom's Hardware review of the top nVidia graphics cards, they use a higher end MoBo, and processor. This is the ideal system to run SLI at it's best. They don't include a BFG OC video card though.

http://www.tomshardware.com/2005/12/...ia/page39.html

[brunch]

Thanks for the input!

But even the lowest benchmark there was a full 1300 marks above mine--and my cards are OC, with a top mobo. And a guy told me he was getting 9000 with 6800 Gt at Ultra speeds in SLI with a 3GHz processor. Besides, game performance should be improving at least to the point where it's noticeable. As it is, I can't tell if it gets better or worse.

Many if not all of the fps tests as well as the benchmark test showed a pronounced improvement when in SLI mode on the website you linked to. Would I need a better processor for that kind of boost?

Again, thanks!
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[giantkoreandorq]

Yea, I think getting a better processor would help. However, if you're into gaming, an AMD processor would be much better. Here's some charts on video performance in DirectX and OpenGL from Tom's Hardware.

OpenGL:
http://www.tomshardware.com/2005/11/...05/page24.html

DirectX 9:
http://www.tomshardware.com/2005/11/...05/page29.html

About that guy who has the 9000 score, I don't think he had it at max resolution. There was another test that involved 2x 6800GT SLI on max settings, it only scored a 4891, while the 2x 7800GTX scored a 9118. Again, Tom's Hardware used a superior test setup. I would doubt that guy could get a 9000 on maxed out settings. Here's a better comparison done a little bit earlier.

http://www.tomshardware.com/2005/12/...ii/page18.html

[rspassey]

Those scores aren't normal, I can almost acheive those with dual 6800s... what you should check is to make sure that you have x64 drivers if you are on Windows XP 64 bit and if not, then make sure you have 32 bit drivers, and make sure you installed the drivers on each card, not just once, it has to be on each card. Make sure you are also keeping track of what AA and AF you are using, bumping them up as high as they will go reduces frames per second and you don't necessarily see a visual improvement.

[brunch]

Thanks for the info!

I installed the dhzeropoint 0.8195 driver again and doublechecked that it's 32 bit. I ran a benchmark in single then in alternate frame rendering mode. I was optimistic, because the single score was 8106, but then the SLI score was 8103. Lamatron.

At least now I know for sure it isn't normal.

Thanks again!
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[rspassey]

Did you make sure you went into device manager and loaded the drivers on each display device.

[brunch]

Device manager said both devices have the same driver.

I won't be able to do anything for a while because I'm at Lake Tahoe, but I can reply to posts at this internet cafe.

Thanks!
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