An SLI problem when measuring graphics performance?

[Cookie Monster]

Hello all,

I have a brand new high-end system with main components Asus A8N-SLI Deluxe, Athlon 64 FX-55, 4x512MB=2GB RAM Geil Dual Channel, 2x300GB/16MB Maxtor SATA, and 2xAsus EN6800 GT/SLI (activated). The OS is WinXP Pro SP2. All recommended Bios and Windows settings for the basic optimisation of the system have been set all right.

Testing in 3DMark2005 gives slightly above 8,900 points, which in comparison with others seems totally normal for this non-overclocked latest-technology-system of mine.

Then I really become when testing in PerformanceTest 5, getting only 437 points in total. The only two comparable ones to download from Passmark for comparison give above 900 and 1,100. respectively. My old PC with Athlon XP 2000+, 1 GB RAM, Radeon 9800 Pro and OS Win2k, gives 373 points in total. The graphics results were incredibly bad, for partial tests '2D-shapes' much less and '3D-Simple' less than my old PC, and in the other ones only somewhat above or the same as my old PC. There are some limited question marks for the CPU and the disk performance as well but in no way comparable to the very odd results in the graphics testing (of course contributing much to the low total points as well).

Can anyone at Passmark or anyone else explain these results to me? Can it be that your programme does not work with SLI? The other two fast ones had 'only' high-end single cards (ATI X800 cards even do not work in SLI).

Looking forward to someone commenting these results and trying to answer my questions!

[David (PassMark)]

> Can it be that your programme does not work with SLI?

In fact it is the other way around.

As far as I know, NVidia has provided zero information on SLI for
developers. So there is no way to write software that is sure to work with
SLI.

Inside the NVidia device driver is a list of about 80 software applications
that work with SLI. If your software is not in this NVidia list then the
device driver will not attempt to use SLI for that application. (Only 80
applications out of 100,000's of applications available for Windows!).

In recent versions of the NVidia device driver you can add to the list of
applications, but it has also been stated elsewhere that you can easily
crash your machine if you pick the wrong settings, and some applications
(For example, Microsoft flight simulator will never work with SLI)
See these pages,
http://www.graphics.tomshardware.com...rmance-05.html
http://www.nzone.com/object/nzone_sli_appprofile.html

So in fact we believe it is the Nividia device driver that doesn't know what
to do, rather than a problem with PerformanceTest.

-------
David

[Cookie Monster]

Dear David,

I really appreciate your answer, since it explains things, i. e. confirms my suspicions in this matter. There had to be some logical explanation! It is very typical that MS, Nvidia and many other large hardware/software vendors (I cannot list all here) seldom succeed in doing the perfect thing (though their ads say so). Instead they let us, the users, have repeated hard fights with our beloved PCs to really make use of all (mostly!) fascinating features they provide us with.

The SLI-related code you miss may be seen as some kind of secret at this stage but I really hope that Nvidia will change this bad policy very soon. Open codes are normally advantageous also for their providors, by giving the total market a push ahead with a positive net effect on their own sales.

Finally, the viewpoints and solutions that I find at the two web sites you linked me to actually give me some hope and even some direct tools for increasing the usefulness of my SLI system. Many thanks, David! Let's fight on with our PCs and sucking vendors! I urge Nvidia to tell you the codes you need to further improve the usefulness of your Performance Test!

[RandySavage]

I have SLI and some of the passmark video benhcmarks are respectable and others are miserable.

Strangely, and perhaps related, is that my buss in passmark shows as PCI, not PCI express. I tried looking for a big red button marked "press for PCI-Express Activiation" but nothing jumped out at me on the motherboard or in the manual.

[David (PassMark)]

The reporting of the PCI slot types doesn't effect how the tests are run.

I just checked on my machine using V6 of PerformanceTest. PCI-X and PCI-Express slots are being reported.

I don't think there is anyway to activate (or deactivate PCI-E).

There are more comments on poor SLI performance here,
http://www.passmark.com/forum/viewtopic.php?t=306

----
David