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Gtx 970 running at pcie x4

Stiffler05

Stiffler05

Stiffler05

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Joined
13 Jul 2005
Posts
132
Hi guys,
I'm having some issues with my gpu at the moment as it frequently runs at pcie 2.0 x4 and then occasionally at 2.0 x16 (using the render test in gpu-z).
I have a gtx 970, asrock z77e-itx, i5 2500k at 4.4 ghz and a 600W psu.
I've been trying to troubleshoot the problem for a while and have tried reseating the gfx card, resetting the cmos and changing the pcie settings in the bios to no avail.
Occasionally when I boot up the pc the gpu runs at x16 but the majority of the time it runs at x4.
The software, settings or hardware hasn't changed between boots but I don't understand why it works at x16 occasionally and not at others.

Has anyone had experience of something like this or has some suggestions?

Thanks, Steve.
 
this is normal behaviour. PCIe lane count will drop when the lanes are not required or nothing is happening. If I had to venture a guess to save a little bit of power somewhere. When you put a load on it like you do with GPU-z, it kick's up and behaves as expected.

Long story short, behaviour your seeing is normal and happens on all my systems.
 
Hi,
Sorry, perhaps I didn't explain very well.
When I run the render test in gpu-z, the majority of the time my gpu idles at pcie x1 2.0 and then ramps up to x4 2.0 under load.
Occasionally when I boot the computer the gpu is idling at x4 2.0 and then ramps up to x16 under load.
This is what I don't understand. It's the irregular pcie speeds.
 
Radox-0 said:
this is normal behaviour. PCIe lane count will drop when the lanes are not required or nothing is happening. If I had to venture a guess to save a little bit of power somewhere. When you put a load on it like you do with GPU-z, it kick's up and behaves as expected.
Click to expand...

This should be controlled by "PCI Express->Link State Power Management" under your Power plan settings (on Windows 7 at least), by using less lanes in theory it saves a tiny bit of power
 
Fixed similar issue on my GTX 970 by not only re-seating it (that didn't work on its own) but seating it in a different PCI-E slot, then seating it back on the x16 PCI-E slot. That won't help in your case with an ITX, though. However, apparently it was running at x16 all the time anyway (on load), and it was just a GPU-Z thing. The PCIe link speed sensor in HWiNFO64 confirmed it was fluctuating from 2.5GT/s idle to 8.0GT/s load (on PCI-E 3.0).

Maybe try DDU (the Clean and Shutdown for installing a new graphics card option). Might just reset everything more completely.

Most likely there is no actual issue, other than GPU-Z not reading it correctly. Try a benchmark like Valley/Heaven on Extreme 1080p and post results if you want.
 
I'll give DDU a try over the weekend as that's something I've not done yet. I'll also try heaven extreme and post back my results.
Thanks for everyone's help.
 
Update:
I tried DDU but nothing changed during the gpu-z render test, still x4 under load.

I ran heaven at 1080p, ultra quality, extreme tessellation, aa x8. Score 1400 with no OC. Does that seem ok?

Using HWiNFO64 sensors the pcie link speed is at 2.5 GT/s when idle and 5.0 GT/s when under load.
 
Last edited:
Stiffler05 said:
Update:
I tried DDU but nothing changed during the gpu-z render test, still x4 under load.

I ran heaven at 1080p, ultra quality, extreme tessellation, aa x8. Score 1400 with no OC. Does that seem ok?
Click to expand...

Bang on where you'd expect most stock clock 970s. And 1500-1600+ when overclocked.


Stiffler05 said:
Using HWiNFO64 sensors the pcie link speed is at 2.5 GT/s when idle and 5.0 GT/s when under load.
Click to expand...

How it should be, for PCI-E 2.0 x16.

So it's a GPU-Z quirk/bug.
 
Isn't the shift from 2.5 GT/s to 5 just the change in transfer rate from pcie 1.1 to 2.0 when under load?

Shouldn't the bandwidth of x1, 4, 8 & 16 change too. So at x4 I'm only getting 2GB/s, where as at x16 (if it was working correctly) I'd be getting 8GB/s.
 
Stiffler05 said:
Isn't the shift from 2.5 GT/s to 5 just the change in transfer rate from pcie 1.1 to 2.0 when under load?

Shouldn't the bandwidth of x1, 4, 8 & 16 change too. So at x4 I'm only getting 2GB/s, where as at x16 (if it was working correctly) I'd be getting 8GB/s.
Click to expand...

You can't get 8.0 GT/s with PCI-E 2.0. That's PCI-E 3.0.

I understand that the x4 etc values ought to be changing but actual performance is bang on if that's any consolation. In time, with a GPU-Z update or something, you'd see it represent the values accurately. Unless you find a fix for that bug on your ITX board, which isn't as simple as with micro-ATX or ATX.

You could borrow a different card if possible, that might get proper values showing again and then carry through when you put the 970 back in.
 
Danny75 said:
You can't get 8.0 GT/s with PCI-E 2.0. That's PCI-E 3.0.

I understand that the x4 etc values ought to be changing but actual performance is bang on if that's any consolation. In time, with a GPU-Z update or something, you'd see it represent the values accurately. Unless you find a fix for that bug on your ITX board, which isn't as simple as with micro-ATX or ATX.

You could borrow a different card if possible, that might get proper values showing again and then carry through when you put the 970 back in.
Click to expand...

Yeah I know you can't get 8GT/s on pcie 2.0. But the bandwidth is different from what I understand, pcie 2.0 x16 should be 8GB/s.

I suspect my motherboard is possibly faulty, so after trying so many different fixes and changes I think I have to accept that either gpu-z is wrong or my gpu is running slower than it should. I appreciate everyone's help. I guess at worst I'm losing 10% performance at x4 which I can make up by overclocking my gpu.
 
Stiffler05 said:
Yeah I know you can't get 8GT/s on pcie 2.0. But the bandwidth is different from what I understand, pcie 2.0 x16 should be 8GB/s
Click to expand...

Ah you were talking about bandwidth, then it would be 16 GB/s.


Stiffler05 said:
I suspect my motherboard is possibly faulty, so after trying so many different fixes and changes I think I have to accept that either gpu-z is wrong or my gpu is running slower than it should. I appreciate everyone's help. I guess at worst I'm losing 10% performance at x4 which I can make up by overclocking my gpu.
Click to expand...

It's been seen before and in most cases it's just some sensor-reading issue. http://www.tomshardware.co.uk/answers/id-2655093/pcie-bus-showing-x16.html

Try blowing dust out from the slot too.

I removed my 970's core and mem overclock and tested with Heaven, getting a score of 1435. Bear in mind it still boosted to 1392MHz core (Afterburner reading not the incorrect Heaven reading). Maybe yours doesn't boost quite that much.

Overclocked at 1565MHz core and 8000MHz memory, the score is 1631.

Given that, if yours boosts to around 1360MHz at stock then the score of 1400 is spot on.
 
Danny75 said:
Ah you were talking

Try blowing dust out from the slot too.

I removed my 970's core and mem overclock and tested with Heaven, getting a score of 1435. Bear in mind it still boosted to 1392MHz core (Afterburner reading not the incorrect Heaven reading). Maybe yours doesn't boost quite that much.

Overclocked at 1565MHz core and 8000MHz memory, the score is 1631.

Given that, if yours boosts to around 1360MHz at stock then the score of 1400 is spot on.
Click to expand...

I've blown dust out of the slot a few times but it made no difference.

Overclocked at 1500mhz on the core and 8000mhz on the memory I get 1550 in heaven which looks similar to your score.

Here's the weird thing. Two days ago I turned my pc on, checked gpu-z and it showed the 970 was running at 2.0 x16 under load. When I then launched msi afterburner, all the sensors (which I had turned off months ago) had somehow been switched back on (there was no update to afterburner). Two pc restarts later the 970 was back to 2.0 x4 under load and the afterburner sensors were turned off again!
I've tried uninstalling afterburner to see if it was affecting the pcie speed but it didn't change anything. It's very random and perhaps it suggests there's a software problem.
 
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