• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

New gpu not detected in upper PCI-E slot

Joined
Feb 11, 2009
Messages
5,942 (0.99/day)
System Name Cyberline
Processor Intel Core i7 2600k -> 12600k
Motherboard Asus P8P67 LE Rev 3.0 -> Gigabyte Z690 Auros Elite DDR4
Cooling Tuniq Tower 120 -> Custom Watercoolingloop
Memory Corsair (4x2) 8gb 1600mhz -> Crucial (8x2) 16gb 3600mhz
Video Card(s) AMD RX480 -> RX7800XT
Storage Samsung 750 Evo 250gb SSD + WD 1tb x 2 + WD 2tb -> 2tb MVMe SSD
Display(s) Philips 32inch LPF5605H (television) -> Dell S3220DGF
Case antec 600 -> Thermaltake Tenor HTCP case
Audio Device(s) Focusrite 2i4 (USB)
Power Supply Seasonic 620watt 80+ Platinum
Mouse Elecom EX-G
Keyboard Rapoo V700
Software Windows 10 Pro 64bit
So I have an Asus p8p67 Deluxe B3 motherboard

I have been running an AMD HD6950 for a long time now and it has been fine, however due to an oppertunity I now got an RX480.
When I install it in the same PCI-E express slot the HD6950 has been working fine in for years, I get the long deep then 3 beeps error code and no image.
That code means the motherboard is not detecting the a VGA.

When I put it in the lower pci-e express slot it works fine.

Anyone got any clue why the upper slot that worked fine for years to this day suddenly cannot detect the new gpu?


UPDATE:

So here is what I did so far.

1. Cleaned the mobo card slots, a long shot but whatever, it did not help.
2. I was on legacy, now im on UEFI in the boot menu and it did not change anything.
3. Tried messing with the PCI-E slots speed, setting it to Auto, X4, X2, did nothing.
4. The bios Im using is the latest bios available, 3801, so no updates for that.

Currently my old HD6950 is in the upper slot doing just fine.
The RX480 only seems to work in the lower slot (at the lower x8 speed)

I guess I have to try to put the card now in another pc to see if it even wants to work at x16 to begin with :L
 
Last edited:
Try enabling both EFI and Legacy modes on boot devices.
 
Do you have another PCIE slot that is full bandwidth. Make sure all signal pins are clean on the new gpu. Make sure the mobo bios is updated too. If no dice contact Asus Live chat and ask there. What brand of RX480 do you have? Hope it wasnt minning, make sure smds near pcie blade are not missing.
 
Try enabling both EFI and Legacy modes on boot devices.

Ill give that a go soon

Do you have another PCIE slot that is full bandwidth. Make sure all signal pins are clean on the new gpu. Make sure the mobo bios is updated too. If no dice contact Asus Live chat and ask there. What brand of RX480 do you have?

Well idk, the mobo can handle crossfire.
The signal pins should be clean as it does work in the lower pci-e slot, it just does not work in the upper one where I had my previous gpu in till today.
Its an older mobo so not many updates, but since when are bios updates needed for a gpu?
As for the brand, cant say right now.
 
Ill give that a go soon



Well idk, the mobo can handle crossfire.
The signal pins should be clean as it does work in the lower pci-e slot, it just does not work in the upper one where I had my previous gpu in till today.
Its an older mobo so not many updates, but since when are bios updates needed for a gpu?
As for the brand, cant say right now.

Ok you are going to a card that is soley uefi and it is common for p67/z68 boards to have this problem. Bios updates help improve hardware compatibility too, since this card is newer than 2012/2013 a bios update typically resolves oddities like this. Does the card work at max bandwidth in the other slot? If it does great. By the way what cpu are you using exactly?

Another thing to try is push the card in fully then jently tug on it to move it out 1/16 of an inch out. That was a tip in another thread I saw.
 
No other slot options...

  • Expansion Slots
    1 x PCIe 2.0 x16
    1 x PCIe 2.0 x16 (x4 mode, black) *1
    2 x PCIe 2.0 x1
    3 x PCI
*1: The PCIEX16_2 slot shares bandwidth with the PCIEX1_1 slot, PCIEX1_2 slot and USB3_34 connector. The PCIEX16_2 runs at x1 mode by default for system resource optimization.
 
Im sorry I dont know what you are trying to say.

Your board doesnt allow max bandwidth in other slots, only the top slot. I would try the gpu in another machine to verify it works in the full bandwidth slot, if it fails there too, it is possible the card you got is damaged. Where did you buy it from?
 
Your board doesnt allow max bandwidth in other slots, only the top slot. I would try the gpu in another machine to verify it works in the full bandwidth slot, if it fails there too, it is possible the card you got is damaged. Where did you buy it from?

ah right right right, will try that, Its from a pre-build pc from a local store that is trustworthy
 
Quite possibly a UEFI issue rather than a physical issue. Check the BIOS and try CSM/Legacy and see if it works.
 
Ok you are going to a card that is soley uefi and it is common for p67/z68 boards to have this problem.
I have yet to encounter this problem, though I'm not saying it's unlikely. Far more likely to be oxidation on the slot contact pins and/or card connector pins. I'd recommend a cleaning with contact cleaner that removes oxidation.
 
once again some of tpu showing exactly how much they don't know

in the bios under the boot-tab change the pci rom priority to from efi compatible to legacy
early asus boards have really terrible uefi support
./thread
 
UPDATE:

So here is what I did so far.

1. Cleaned the mobo card slots, a long shot but whatever, it did not help.
2. I was on legacy, now im on UEFI in the boot menu and it did not change anything.
3. Tried messing with the PCI-E slots speed, setting it to Auto, X4, X2, did nothing.
4. The bios Im using is the latest bios available, 3801, so no updates for that.

Currently my old HD6950 is in the upper slot doing just fine.
The RX480 only seems to work in the lower slot (at the lower x8 speed)

I guess I have to try to put the card now in another pc to see if it even wants to work at x16 to begin with :L
 
UPDATE:

So here is what I did so far.

1. Cleaned the mobo card slots, a long shot but whatever, it did not help.
2. I was on legacy, now im on UEFI in the boot menu and it did not change anything.
3. Tried messing with the PCI-E slots speed, setting it to Auto, X4, X2, did nothing.
4. The bios Im using is the latest bios available, 3801, so no updates for that.

Currently my old HD6950 is in the upper slot doing just fine.
The RX480 only seems to work in the lower slot (at the lower x8 speed)

I guess I have to try to put the card now in another pc to see if it even wants to work at x16 to begin with :L

Yup, if no dice then card is goofed
 
The RX480 only seems to work in the lower slot (at the lower x8 speed)
There have been a metric ton of benchmark tests that have proven that most GPU's can not saturate an 8X PCIE bus link. If you don't believe this, run a benchmark with your 6950 in the 16X slot, then rerun the same with it in the 8X slot. Each should be within a statistical margin of error(approx 3%-4%). You will not see a difference with the RX480 either. Try it to see for yourself and let us know your results.
 
There have been a metric ton of benchmark tests that have proven that most GPU's can not saturate an 8X PCIE bus link. If you don't believe this, run a benchmark with your 6950 in the 16X slot, then rerun the same with it in the 8X slot. Each should be within a statistical margin of error(approx 3%-4%). You will not see a difference with the RX480 either. Try it to see for yourself and let us know your results.

Yeah this is true, it does not seem to hurt the performance.
So this will work, but its just an odd issue, I have no idea why a gpu would not work (why cant things ever be easy) in one slot but work in the other.

Also from a practical standpoint regarding airflow etc it would be better if it was in the upper slot but it is what it is I guess.

Thanks all, if anyone has another wacky idea that might be causing the issue ill glady hear it.
 
I would still verify the card works at max capability in another system.
 
Back
Top