Top PCIe slot gives a VGA LED + no video output, bottom works fine.

[ACBRAH]

CPU - i5-10400F
GPU - GTX 1660 and GTX 1660 Ti
Motherboard - MSI Z490 Gaming Plus
PSU - be quiet pure power 11 500W

My build was working for at least 2 months without problems. But lately I did a range of things like change around GPUs, cable management and installed new fans.

Now when my GPU is plugged into the top PCIe slot I get a white LED light on VGA and no video output. The fans spin. If do it in the bottom slot it works fine. Things I've tried is different GPUs get the same problem. Checked all the cables. I've removed and reinserted the CPU. I even changed the Z490 board around with another of the same type and same issue.

It points to the CPU at this stage so I'm going to do an RMA with scan. Has anyone experienced this before? I have searched a lot on this issue and a few posts suggest the CPU. Just seems very odd that it occurred all of a sudden. Mind it was a my first build so could be something I did wrong but I rebuilt with a new motherboard which didn't fix the issue.

[ik9000]

alternatively you could have borked the top slot. Not uncommon if you try to yank the card out without disengaging the latch properly first. Look carefully, is there any cracking around the edges of the housing where it joins the motherboard?

wait what, you've swapped the motherboard and are still having the same issue? Have you checked BIOS/UEFI doesn't have a boot preference with the default manually set to a certain slot? What does the manual say is the primary pciex16 slot? Is that top slot definitely the right kind, and is its PCIe version set to the right generation to match your card (gen 3x16)?

Do you have any other peripherals/cards/nvme/sata etc that cause the pcie slot to drop bandwidth to allow the combination of wider connections? It's not uncommon for some mobo to drop pcie16 speed to allow all the sata/nvme slots to be populated.

[ik9000]

looking at the msi datasheet the top slot is the CPU fed pcie3x16 slot so if it's giving the same issue in two different mobo then it could well be the cpu. Did you make the changes with the power off and everything earthed? Have you checked all power cables are properly seated and the GPU is being fed by independent non-daisy-chained cables of the right amperage? If you reseated the CPU, did you check for no bent pins etc?

[Pob255]

you should also be able to set the pci-e mode in the bios, try taking it off auto and manually setting it to pci-e gen3, then try pci-e gen2

Also check the slot for damaged pins, any which are bent out of alignment

[ik9000]

you should also be able to set the pci-e mode in the bios, try taking it off auto and manually setting it to pci-e gen3, then try pci-e gen2

Also check the slot for damaged pins, any which are bent out of alignment

if he's tried two mobo it's unlikely to be the slot pins, CPU pins possibly?

[ACBRAH]

looking at the msi datasheet the top slot is the CPU fed pcie3x16 slot so if it's giving the same issue in two different mobo then it could well be the cpu. Did you make the changes with the power off and everything earthed? Have you checked all power cables are properly seated and the GPU is being fed by independent non-daisy-chained cables of the right amperage? If you reseated the CPU, did you check for no bent pins etc?

Yes two differenot motherboards + two different GPUs same issue. All cables were checked, I built and rebuilt a few times. GPU was getting the 8 pin cable from the PSU. I checked the socket for bent pins but nothing (will post pictures shortly). On the CPU end it doesn't have pins that protrude so wasn't sure what to look for there (I've since posted this out to Scan).

It did seem to point at the CPU after all the troubleshooting I did. Upon googling some people did have similar issues where the bottom slot worked but not the top and it was resolved by a new CPU. Wish I knew what is the issue, hopefully scan will know assuming they test RMA'd items before sending the new one out.

[ik9000]

ooh before RMAing what bios are you running? Does the mobo need a bios update to support the chip model? Sometimes boards ship with early bios that later versions iron out.

[ACBRAH]

ooh before RMAing what bios are you running? Does the mobo need a bios update to support the chip model? Sometimes boards ship with early bios that later versions iron out.

https://imgur.com/a/mPQsxMs These were the sockets. 1-3 are the first board I used for 2 months successfully. 4-6 the new one I tried yesterday. They look ok to my untrained eye.

Both were on the latest. The new one I put the GPU in 2nd slot, accessed windows and got the bios then flashed it to the latest. Still didn't work!

I'm not sure of how the CPU links to the 1st pcie slot but somethings probably shat itself there. Hopefully that's my problem. PC troubleshooting isn't my style.

[ACBRAH]

As an update scan confirmed cpu was faulty as they also got no video output in the top slot pcie.