super slow CPU score when using single card in CrossFire Mobo

[Chesebert]

I have a Gigabyte P35 mobo with Crossfire support, Intel C2D @3.2Ghz, X850XT PCIE, and WinXP.

The problem is running the X850XT in slot 1, or lower slot, on the motherboard. I ran several test under 3dmark 2k3 and 2k5, the graphics scores were fine in both cases, but the CPU score were 50% of their normal value.

This problem goes away if I move the X850XT from slot 1 to slot 0, or the higher slot, on the motherboard.

I can't use the slot0 on the motherboard on a daily basis, because it blocks the HD cage in my case!

Is this normal? Am I forced to use Slot0 instead of Slot1 in a crossfire mobo?

 

[Stumps]

the second PCI-E slot on the GA-P35-Dxxx series boards is only a PCI-E x4 slot, so it is considerably slower than the first PCI-E slot.

you will need to rearange things in the case so the Video card doesn't clash with the Harddisk cage if you want the best performance from your system.

 

[Chesebert]

Well then why is the GPU scores between the 2 slots essentially identical but the CPU scores are not?

 

[Stumps]

Originally posted by: Chesebert
Well then why is the GPU scores between the 2 slots essentially identical but the CPU scores are not?

the second PCI-E x4 slot is causing a bottleneck somewhere, I would say it could be a video driver issue of some sort as the X850 was never ment to be run at only PCI-E x4.

I don't have a crossfire board handy to check for you, maybe if you ask Apoppin nicely, he might be able to give you some advice, he has a GA-P35-DS3P which is a crossfire board.