GPU-Z Bus Interface Reporting

[stahlhart]

For a P67 motherboard, where running SLI sets the cards up as x8, is it normal for GPU-Z to report both of the cards/slots as PCIe 1.1?

The two slots I'm using are PCIe 2.0 x16_1 and PCIe 2.0 x8_3 (PCIe 2.0 x16 slot running as x8).

It was something I noticed when installing the 275.33 drivers last night. I would have thought that the slots would continue reporting themselves as 2.0. What appears to happen with GPU-Z is that the slot will initially report as 2.0, but then after a few seconds switches to 1.1.

 

[MiRai]

After reading this I went ahead and checked as well and I see the same
behavior. However, as soon as I fire up a game and actually make the GPU
work, GPU-Z goes back to reporting it as 2.0. I guess all is well.

 

[stahlhart]

I appreciate your checking this; thanks much... welcome to the forums, too.

What actually happened that alarmed me was that it was Windows that spoke up first, not GPU-Z... in the process of installing 275.33, I got a message in the lower-right corner that the GPU was installed in a low-performance slot, and that I should move it (them?) to a better one. I'd never seen that message before, and I haven't moved the cards since I built the system new. I rolled the drivers back to 270.61, and then 260.44 (the ones came with the cards) and didn't get the warning either time.

I ran Vantage with the cards in SLI, and am still getting the same approximate score I always have (around 39K), so mabye there's no issue at all here to be concerned about. But it was just weird getting that Windows warning about the slot bandwidth.

 

[stahlhart]

Okay, here's what I'm not getting -- I'm just running on one card now, in the first slot. Why are the card and slot negotiating down to 1.1 from 2.0?

 

[stahlhart]

Looks like my Google-fu really sucked last night, and that this is a long-standing issue going all the way back to X38/X48/X58, and only with Nvidia cards. Whether or not it's actually a problem affecting performance is another question entirely, apparently.

http://www.xtremesystems.org/forums/showthread.php?t=249130

 

[stahlhart]

Aaaaaand it's a non-issue after all. Appears to be some sort of power management function in the drivers -- if I set up a game windowed, I can see both cards negotiating back up to 2.0 x8 in GPU-Z when 3D kicks in. I guess I just panicked unnecessarily when Windows spoke up about the degraded slot that one time (still wondering about that, though).

Anyway, just ignore me -- carry on. :whiste:

 

[betasub]

If desired, you should be able to stop switching to the lower mode through Control Panel > Power Options > Advanced Settings > PCI Express > Link State Power Management

Oh, yeah, and Edit button FTW!

 

[stahlhart]

Link State Power Management is already off.