P8Z68-V Pro Problems with PCIe Slot 1 link speeds

[Thunderman]

I have had the P8Z68-V Pro for 2 days and was experiencing the following issues with all three bios versions (501, 606, 706) and with and without overclocking.

I have the 2600K CPU, DDR3-1333 Kingston Memory from the Qualified Vendor List and an ATI 4870X2 VGA.

- I sometimes boot the system to find that my PCIe 2.0 speed is set at 1X games will then run at 20 fps max and if i run the windows experience index i get 5.9 in Memory section. (PCIe transfer speed as measured by the Pcie speed utility is around 300mb/s between the Cpu and the Gpus).

If i put the system to sleep then upon waking up the link speed is 16X and performance is up to normal levels. PCIe transfer speed are up to around 5.8GBs ~~ 6GBs

However it would randomly drop back to either 1X or 8X or even 4x and if it happens during gaming then it is easily detected by a clear drop in framerates.

I first though it could be related to the Integrated GPU and to Virtu, so i disabled both yet it still occurs, i also tried setting VRM Duty Control to extreme thinking it could be related to a voltage drop without success.

Any help would be great as i first start having those issues with this board, the CPU, RAM and VGA were all running great on my previous P67 board.

Thank you,

[Raja@ASUS]

Is this a fresh OS and driver install?

If it is, try disabling C3 and C6 in the CPU Configuration section of UEFI.

[Thunderman]

Hello and thanks for the quick reply,

Yes this is a Fresh OS install and all drivers are up to date.

I have also tried to put the 4870X2 in the second PCIe slot which caused it to default to PCIe 2.0 8X and the same issue occured after few minutes of gameplay the PCIe slot 2 connection was dropped to 1X.

I also tried with C3 and C6 report disabled as you mentionned but without success.

[Raja@ASUS]

Hello and thanks for the quick reply,

Yes this is a Fresh OS install and all drivers are up to date.

I have also tried to put the 4870X2 in the second PCIe slot which caused it to default to PCIe 2.0 8X and the same issue occured after few minutes of gameplay the PCIe slot 2 connection was dropped to 1X.

I also tried with C3 and C6 report disabled as you mentionned but without success.

You won't get anything higher than 8x on the second PCIe slot as there are only 8 lanes running to that connector (the CPU only has 16 lanes, 8 of which are hard-wired to PEG slot 1 while the remaining 8 are routed via switches).

[Thunderman]

I only tried Slot2 to test if the issue was only related to the first Slot or not, I definetely will be using Slot 1 as i need the full X16 speed.
But this issue is really tricky, as everything was running fine with the P67 mobo.

Could it be a bad Motherboard ? or just a setup parameter as maybe the 4870X2 is drawing a lot of power and the DIGI+ VRM is not comfortable with that ?

[Raja@ASUS]

Could it be a bad Motherboard ? or just a setup parameter as maybe the 4870X2 is drawing a lot of power and the DIGI+ VRM is not comfortable with that ?

DIGI+ VRM has nothing to do with PCIe speeds. This seems to be some kind of OS/driver issue to me rather than the board (would be more common place if it were a board problem).

-Raja

[Thunderman]

OK i will try to do another install with other drivers, the only thing is that when PCIe speeds drop if i run Win7 Experience Index i get 5.9 in the Memory Section instead of the usual 7.8

Does this indicate something ?

Thank you for your support Raja

[Raja@ASUS]

I never use WEI so can't comment on that. The only real gauge is why your frame rates drop the way they do. In any case, do a fresh install with the latest drivers and if that does not help contact your local ASUS Support department and see what they suggest.

-Raja

[Thunderman]

If Anyone has the same setup running a 4870X2 with the P8Z68, i would recommend if you are having issues with the PCIe link speeds to use an older Catalyst driver, at least it seems to reduce the frequency of such issues occuring.

I did a fresh install with the latest Catalysts 11.8 and 11.9 yet the PCIe link speed dropped very frequently from the original 16X to 1X or 4X slowing down most games to a crowl.

I decided then to try an old 11.4 driver and it seemed to partially solve the issue,
only one link drop occured during multiple hours of gaming.

I sure hope to find a solution, i will update this thread if any,
else i might send the 4870X2 to retirement but would then need a worthy replacement.

[thosankos]

Hello I write from Italy and I apologize for the spelling. :-p

I have the same motherboard and also the same problem.
I use a nvidia engtx570 and are not able to configure the graphics ...
the pcie is not working properly.

now my pc is the shop for service, but they fail to improve the situation.
I also ask for help

I participate in the 3rd to keep me updated. :-)
asus :-(