Asrock Z68 Extreme7 Gen3- SLOW pcie with only 1 slot

[relee]

Hi everyone.

I have a tough problem that's puzzled me for weeks. I have an

ASRock Z68 Extreme7 Gen three running Windows7 x64 SP1
AMD 6970 GPU card in the first slot.
Intel i7 2600-K
8GB main memory DDR3 1333Mhz.
1 SATA2 HD
Nothing else, and almost no additional software.

The board functions fine and I have had no problems except the speed of the PCIE bus is VERY SLOW, about 1/4 what it should me.
The GPU in slot one should get about 6GB/s bandwidth (x16 2.0) but gets only 1.5GB/s. The board has 5 slots a mix of x16, x8 and x4, and all of them are equally slow. I have tried several different models of AMD GPUs including 6870. 6970, and 7970. All the same.

I have spent weeks updating and reinstalling every version and combination of bios , intel drivers, and bios setting. Nothing helps.

I measure the PCIE bandwidth with several programs like BufferBandwidth.exe PCIEBandwidth.exe (AMD), Sandia, and my own programs. Always the same at 1.5GB/s.

This is an odd problem because GPu-Z is reporting the correct PCIE configurations for the GPU and the motherboard. ie PCIE x16, v2.0 running at PCIE x16, v2.0.

AMD has looked at the data and say its most likely the mainboard, which I believe about 80%. But it might also be the GPU driver having trouble with the advanced design of this mainboard???

Does anyone else have any experience with AMD GPUs in this board? Especially can you confirm the PCIE bus speed is up to, well, speed!

Or, maybe someone has seen this kind of problem with other boards/GPUs????

Many thanks in advance for any ideas. When I do get to the bottom of it I will post the final conclusion here.

 

[unclejehmimah]

Hi everyone.

I have a tough problem that's puzzled me for weeks. I have an

ASRock Z68 Extreme7 Gen three running Windows7 x64 SP1
AMD 6970 GPU card in the first slot.
Intel i7 2600-K
8GB main memory DDR3 1333Mhz.
1 SATA2 HD
Nothing else, and almost no additional software.

The board functions fine and I have had no problems except the speed of the PCIE bus is VERY SLOW, about 1/4 what it should me.
The GPU in slot one should get about 6GB/s bandwidth (x16 2.0) but gets only 1.5GB/s. The board has 5 slots a mix of x16, x8 and x4, and all of them are equally slow. I have tried several different models of AMD GPUs including 6870. 6970, and 7970. All the same.

I have spent weeks updating and reinstalling every version and combination of bios , intel drivers, and bios setting. Nothing helps.

I measure the PCIE bandwidth with several programs like BufferBandwidth.exe PCIEBandwidth.exe (AMD), Sandia, and my own programs. Always the same at 1.5GB/s.

This is an odd problem because GPu-Z is reporting the correct PCIE configurations for the GPU and the motherboard. ie PCIE x16, v2.0 running at PCIE x16, v2.0.

AMD has looked at the data and say its most likely the mainboard, which I believe about 80%. But it might also be the GPU driver having trouble with the advanced design of this mainboard???

Does anyone else have any experience with AMD GPUs in this board? Especially can you confirm the PCIE bus speed is up to, well, speed!

Or, maybe someone has seen this kind of problem with other boards/GPUs????

Many thanks in advance for any ideas. When I do get to the bottom of it I will post the final conclusion here.

Do you have anything in the other slots?

 

[alyoshka]

"Nothing else, and almost no additional software. "
Didn't he answer that in his question itself?

 

[relee]

Do you have anything in the other slots?

No, I purposely placed a single card in each slot.
That's what is so strange.

Thanks for the really fast reply.

 

[antiflow]

No, I purposely placed a single card in each slot.
That's what is so strange.

Thanks for the really fast reply.

Hi, I am currently just setting up the same MoBo, and I recall reading that it is recommended to "use only the PCIe 2 slot" if you want to run a single GPU card.



Hope this helps!

 

[relee]

Hi, I am currently just setting up the same MoBo, and I recall reading that it is recommended to "use only the PCIe 2 slot" if you want to run a single GPU card.


Hope this helps!

Yes, it does!

1. Slot 2 runs at full speed (5.6GB/s).
2. But, slots 1 3 4 and 5 still run at 1/4 speed (1.6GB/s) with only the one card installed.
3. Putting a card in slot 2 seems to turn off the other slots completely.

I did not try slot 2 (the only PCI 3.0 slot) because it's not used with more than 1 GPU, as per ASRock.

So, it looks like a mainboard problem and nothing to do with drivers.

To refresh, AsRock advertises that the board is designed to support:
1. 2 gpus in slots 1 + 3 both running at x16 speeds (one at a time, of course)
2. 3 gpus in slots 1 + 3 + 5 with cards running at X16, X8, and X8 speeds.

This clearly does not work on my MoB. slots 1, 3, 4, 5 always work at about 1/4 speed.

Thanks for waking me up to try slot 2.

I hope you are using only one gpu slot or have better luck than I do.

 

[relee]

Best answer selected by relee.

 

[nikorr]

This topic has been closed by Nikorr