Low Memory Bandwidth on GTX280 X38 and GTX280 issue?

Hi guys,

I wonder if someone with the same kind of setup could check the memory bandwidth achieve between the GTX280 and a X38 chipset based motherboard.

I am running WINXP64 with 8GB of ram and I see only 2.4GB/s (pinned or not) to or from the GPU.

That looks like PCIe Gen1 results to me but the X38 is a PCI e Gen2…
I saw some 5GB/s around in some other posts but that was probably on an Nvidia chipset 780i/790i …

I have the 177.35 driver installed just in case.
Oh and I also have a GF8600GT in the same system on the second PCIe bus.



Have you verified that you’re using the latest motherboard SBIOS?

With the current status of that motherboard, I am happy to have one that works…

I am using an Asus P5E WS PRO and there has been quite a few issues with it.

Current BIOS v503.

I will try to update it but I really hope it won’t mess with it…

Be right back after the update, well in the best case :)

I have just updated to the bios available and it doesnt change a lot.

It has improved my Device to Host to 3.1GB/s but my Host to Device stays at 2.4GB/s.
(Pinned memory for 32MB block) -mode=quick -memory=pinned

Unfortunately for me I am more interested in the Host to Device bandwidth :(

For Information I get HtoD 2.4GB/s and DtoH 2.8GB/s using -mode=quick -memory=pinned -device=1 to test the GF8600…

Obviously the device to device falls to 15GB/s in that case compared with the 112GB/s that I have reported on the GTX280.

Okay, just a guess but I think the GF 8600GT is PCI-E 1.0. Maybe having it in one slot sets both to 1.0? Maybe the motherboard can’t understand having different slots and sets both to the lowest common standard for compatibility? If that makes sense, you might try taking the 8600 out and then benchmarking.

Yes I thought about that too.

So I tried to remove the GF8600 but it didnt change anything unfortunately…

The fact that upgrading the SBIOS changed some of the results further suggests that you’re still hitting an SBIOS problem.

Then I am really out of luck… because I really doubt Asus will do anything about it.

I guess I am good for buying a new motherboard. Probably best if it is based on a Nvidia chipset :) (any recommandation Quad Core Intel, DDR2 ?)

I will try to report that to Asus but somehow I fear that it will just be a loss of time.

Can someone just confirm that they can achieve higher results on a X38 chipset motherboard ?
That way I will know it is a SBIOS problem and not a chipset problem.

Thanks netlama.

UPDATE: I just run the system Info that is provided with 3DMark Vantage under Vista and it is reporting the board running in PCI Express version 1.0.
My guess is that it should have been 2.0…

Just to let you know that after a motherboard bios update this morning, my GTX280 is now working at PCIe Gen2 Speed.

Now back to work :)

Move the GPU from slot PCIEX16_1 to PCIEX16_2. Make sure you keep PCIEX16_1 empty. Now the GPU will run at full Gen2 speed.

This problem is not unique to GTX280, but affect others as well (e.g. 9800GX2, 8800GTS/512).

– Kuisma

Make sure it’s not only random. I.e. check it after a few consecutive cold boots. I updated the BIOS, but it only mitigated the problem. Aprox. one time of two, I still got Gen1 speed.

– Kuisma