# PCIe Slot Voltage Strange Readings



## judewicz (Sep 24, 2020)

Hi everyone.

I am having random freezes. I could not find the culprit yet. When using GPU-Z I found this strange PCIe Slot Voltage Reading.





As you can see the PCIe Slot Voltage goes way down (It marks 1.6V when I hover the mouse around the blank region) under load. I put some load on the video card using FurMark.
It says that this is the 12V rail but it surely isn't close to that voltage under load. It also shows 10.7 V when idle.
Is this normal? Could this be the cause of the random freezes? Who is the culprit?


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## SavageGas (Oct 2, 2020)

I've been waiting for someone to reply that actually knows... But seeing as nobody has...

My PC restarts when when my card starts pulling power, but now that I disabled a Automatic Restart toggle, my PC will also freeze instead. If I run the FurMark 1080 test, that will 80% get me a restart or freeze when it starts or about halfway through. Get HWInfo64 instead and check the actual rail voltage and not (just) the PCIe slot Voltage. My 12V rail drops to 11.5V and then restarts my PC soon after.... I've yet to test my RAM or bench with a fresh Win10, but will so this weekend.


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## StaticVapour (Oct 2, 2020)

Do you have DMM? You could carefully measure the actual voltage from 24 pin connector as example to see what it is. Software readings aren't always truthful, about 11 months ago when i was messing around with spare HD 6770 and hitting 1Ghz on it with trimmer pot on Feedback line. GPU-Z was showing around 1.3V / 1.4V when it actually was bit over 1.65V


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## theonek (Oct 2, 2020)

according to latest version of gpu-z pci-e voltage should be constant 12V and it measures even voltages on 8-pins VGA power connectors, which is again 12V. If you have drops it could be something like faulty PSU or at least misreading sensor info.... At least mine shows constant 12v.


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## Caring1 (Oct 3, 2020)

theonek said:


> according to latest version of gpu-z pci-e voltage should be constant 12V and it measures even voltages on 8-pins VGA power connectors, which is again 12V. If you have drops it could be something like faulty PSU or at least misreading sensor info.... At least mine shows constant 12v.


12V and up to 75Watts through the PCI-e slot.


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## SavageGas (Oct 4, 2020)

Yo Jude, still having PC issues?

(I tried a fresh Win10 install on a clean SSD and reinstalled Remnant. Couldn't get the PC to crash/freeze/restart when running 3DMark Firestrike at 720, 1080 or 4k. Remnant ran for 5 hours without freezing either (and before this reinstall, it ran for 5 mins at most)... Which leaves me confused as I swore I had a PSU issue... but maybe I still do lol vOv )


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## Bones (Oct 4, 2020)

judewicz said:


> Hi everyone.
> 
> I am having random freezes. I could not find the culprit yet. When using GPU-Z I found this strange PCIe Slot Voltage Reading.
> 
> ...



Word to the wise guys - Furmark is a GPU killer. 
Stay away and fine something else to test with.


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## judewicz (Oct 19, 2020)

First of all, sorry for the late answer.
I am still having these freezes, and it seems that this measurement is representative of the problem. I recently had a strange freeze where the screen started flashing with abnormal colors. 
I 've been watching the PSU voltages in the BIOS HW monitor and they seem fine. All CPU voltages are also good. Is it possible that the PSU is faulty solely for the PCIe Slot Voltage bus? I don't want to buy a new one if I am not sure if its faulty. I am inclined to think is the MOBO. I don't have another PSU to test this.
Thanks for all the comments so far.


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## bmgjet (Oct 22, 2020)

Slot power comes from the 24 pin plug on the motherboard. Id be unplugging that and checking the connections of the pins.
Then plug back in and make sure its firmly in place.
Back probe the plug as the computers on and make sure its got a good reading there.
If it does then sounds like theres some high resistance some where going though the motherboard dropping the voltage.
Could even try cleaning the edge connector and pci-e slot to make sure they have good connection.


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## Naki (Oct 23, 2020)

I think you should ask the video card maker tech support about this.


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## Vya Domus (Oct 23, 2020)

That's definitely not normal, the odd thing is that the system shouldn't even be able to boot with that voltage on the 12V rail.


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## FinneousPJ (Oct 23, 2020)

The software reading is meaningless until verified. If you suspect it's in error, you need to perform a measurement of the actual voltage.


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## judewicz (Oct 30, 2020)

Latest news about the issue.
Good news: PCI Express voltage is actually low as measured with a DMM. The GPU-Z measurement is representative of the physical value. 
Bad news: I changed the PC geographic location (I lent it to a friend) and hasn't frozen yet (he has been using it for a week).
Is it possible that my electrical installation affects PC stability?


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## Naki (Oct 30, 2020)

Yes, quite possible.  Using a UPS might help.


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## Sora (Nov 6, 2021)

Caring1 said:


> 75Watts through the PCI-e slot.



66 watts, unless the graphics card is violating pcie spec.
the card only measures the 12v input (12v*5.5a), its not reading the 3.3 line which is 9w.


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