Gen 4.0 GPU not working in Gen 3.0 PCIe slot

alpEy · 1 Oct 2022 at 19:40

Hi guys, I've just purchased a Gigabyte Vision OC 3080 (Rev 2.0) to upgrade my Zotac 2070S but I can't get a POST/'No Signal' with the 3080 installed.

Specs :
Motherboard - MSI Z490 Tomahawk
CPU - 10700KF
RAM - 2x8GB Corsair Vengeance 3200MHz
PSU - RM850X
GPU - 2070S/3080

The 3080 doesn't post in the top PCIe slot, but works in the bottom PCIe slot,
The 2070S posts in both PCIe slots,
Both GPU's post in different PC's..

I've checked most things I know;
DDU my old drivers,
Updating BIOS to the latest,
Default settings in BIOS,
Alternating RAM sticks in the preferred #2 slot,
I even re-seated my CPU & checked for bents pints (none),
I set my PEG0 to Gen 3/2/1/Auto which didn't help unfortunately,
Cleaning PCIe slot/3080 pins (Even if it was dirty the 2070S wouldn't work(?),
I first had a 600W PSU, now I have a RM850X with still isn't working - all cables are clipped in PROPERLY on the GPU & PSU,
Separate PCIe PSU cables to power my 3080 (No daisy chain)

I feel as if my components are fine as they all work vice versa, my motherboard is just having a hard time reading the card in the first/top PCIe slot for some reason.

I did try to update the vBIOS to the only option available, but the Gigabyte's updater is dreadful & even when I found a download it gave me a BSOD...

Is there anything else I can try?

Thanks in advance, it's really driving me crazy! **NOT USING RISER CABLE**

EDIT : I can't really tell which part would need replacing IF any do atall, if it was the GPU it wouldn't work in the bottom slot/another PC with stress testing - If it was the motherboard it wouldn't run other GPU's in the first PCIe slot - And if it was the CPU/GPU lanes, again surely it wouldn't run other GPU's? My mind is blown!

Tetras · 1 Oct 2022 at 21:17

HDMI or DP?

alpEy · 1 Oct 2022 at 21:18

Tetras said:
HDMI or DP?

Tried both, multiple cables - which are confirmed working with the 2070S installed

vince99 · 1 Oct 2022 at 21:28

I was using my 3080 in a MSI Z170 board without issue except, it wouldn`t post if the card was sagging even a little bit, so check its well supported. Other issue i had with that board initially wouldnt post coz the mobo screws were too tight :rolleyes:

the extra weight of your 3080 may be putting pressure on a tight scfrew.....longshots but worth a try

alpEy · 1 Oct 2022 at 21:40

vince99 said:
I was using my 3080 in a MSI Z170 board without issue except, it wouldn`t post if the card was sagging even a little bit, so check its well supported. Other issue i had with that board initially wouldnt post coz the mobo screws were too tight the extra weight of your 3080 may be putting pressure on a tight scfrew.....longshots but worth a try

I've made sure there isn't any sag, I've even tried the mobo flat to eliminate sag completely! I'll loosen off my mobo screws and let you know the outcome

alpEy · 1 Oct 2022 at 22:08

vince99 said:
I was using my 3080 in a MSI Z170 board without issue except, it wouldn`t post if the card was sagging even a little bit, so check its well supported. Other issue i had with that board initially wouldnt post coz the mobo screws were too tight the extra weight of your 3080 may be putting pressure on a tight scfrew.....longshots but worth a try

Well, I was incredibly hopeful when I found a mobo screw hanging on by A THREAD...but no luck, all nipped and still nothing

alpEy · 1 Oct 2022 at 22:56

If anybody has any other ideas please let me know;

I can RMA both the 3080 & my mobo, but since they're both working in different configurations I'd of thought neither are necessarily broken...I can't really afford to be without my PC as it gets used for work too, so those are definite LAST options!

ANDARIAL · 2 Oct 2022 at 09:12

Can you return the gpu?maybe get a different make/or model?

alpEy · 2 Oct 2022 at 09:14

ANDARIAL said:
Can you return the gpu?maybe get a different make/or model?

I can, but it works? It seems more like a configuration issue rather than a hardware issue.

I'm gaming on the 3080 & have benchmarked in the bottom PCIe slot, and it works in the top PCIe slot in a different PC.

VortexA1 · 2 Oct 2022 at 13:57

I read that it could be you need a later bios.
I read a similar thing happened with your same make of board and bios update fixed it. Not exact model but same make.

Ie a motherboard problem that was sorted with later bios.

alpEy · 2 Oct 2022 at 15:27

VortexA1 said:
I read that it could be you need a later bios.
I read a similar thing happened with your same make of board and bios update fixed it. Not exact model but same make.

Ie a motherboard problem that was sorted with later bios.

I have updated to the latest BIOS a couple of days ago, but it still didn't change anything...

I have been debating going back to a BIOS that didn't support 11th Gen CPU's and seeing that makes a different to the PCIe defaulting to Gen 3 possibly, but I don't know if I can downgrade BIOS. I don't have a flashback button ect..

VortexA1 · 2 Oct 2022 at 16:18

I would try out another 3080 and see if problem still exists but I'm 90%+ certain it's your motherboard.

Get one off rainforest and then see if it works,if it doesn't send back the 3080 easy with them ,then you'll know if its the mobo but im certain it's motherboard .I'd try another 3080 just to make sure and if then mobo get a replacement

alpEy · 2 Oct 2022 at 16:22

VortexA1 said:
I would try out another 3080 and see if problem still exists but I'm 90%+ certain it's your motherboard.

Get one off rainforest and then see if it works,if it doesn't send back the 3080 easy with them ,then you'll know if its the mobo but im certain it's motherboard .I'd try another 3080 just to make sure and if then mobo get a replacement

That's what I'm thinking, but again other GPU's work fine in this motherboard

It's so confusing...

You had me confused at rainforest for a moment :cry:

Do you think it's worth buying a second hand one from eBay? I had the chance to own a Z590 Aorus Master today for £100 but missed it now...

VortexA1 · 2 Oct 2022 at 16:38

up to you mate. its just easier to try out a 3080 isn't it you just slot it in. That's what i would do but then i could afford to do that on my credit card then send back -get the refund all done lol. it can be to do with the later pci-e standard on the 3000 series, it shouldnt they are all backwards compatible, tbh any gen 4 3000 series you could try just- which must be rare , a pcie-4 card that that the mobo has a problem with that -as has previous standard ,but can happen as in people reporting online.

That's just what id do you could get a mobo i guess im lazy and would try that first as id find it hard to bother with a mobo swap first lol.
im practically certain it's mobo so get another one if you're willing to do that first - and then put it all in , i'm sure that would sort it. (Famous last words )

I just thought, after you updated bios did you take out the cmos battery and leave it out for maybe 5 minutes? You never know..

alpEy · 2 Oct 2022 at 19:44

@VortexA1

I'll try get in contact with some friends and see if they're willing to let me give their GPU's a try...

I've just my computer apart, rigged up as a test bench on a piece of cardboard with only the essentials connected (incase of a case grounding issue or something) but still no luck, even tried brand new RAM sticks...

I didn't quite leave it 5 minutes no, more like 20/30 seconds which I thought was enough. I may possibly reflash the BIOS and leave the CMOS out for a while then!

Just glad it's working in the bottom slot tbh.

VortexA1 · 2 Oct 2022 at 21:22

alpEy said:
@VortexA1

I'll try get in contact with some friends and see if they're willing to let me give their GPU's a try...

I've just my computer apart, rigged up as a test bench on a piece of cardboard with only the essentials connected (incase of a case grounding issue or something) but still no luck, even tried brand new RAM sticks...

I didn't quite leave it 5 minutes no, more like 20/30 seconds which I thought was enough. I may possibly reflash the BIOS and leave the CMOS out for a while then!

Just glad it's working in the bottom slot tbh.

re 5 mins: I think it's best to be as thorough as possible. i would just leave it out for 5 mins without flashing again, just to give the electronics a complete reset.

alpEy · 2 Oct 2022 at 22:17

VortexA1 said:
re 5 mins: I think it's best to be as thorough as possible. i would just leave it out for 5 mins without flashing again, just to give the electronics a complete reset.

I left it for 10 minutes, unfortunately now change. Just stuck with the VGA debug light on.

GPU Logo lights up & the fans still spin…

alpEy · 2 Oct 2022 at 22:23

@VortexA1

Do you know if it's possible to downgrade my BIOS? I don't have a flashback button or anyway of fixing it if it bricks, but I was thinking of downgrading to version 7C80v13 - Just before 11th gen was supported by my mobo. Maybe it will do something spectacular...who knows!

mickyflinn · 2 Oct 2022 at 22:34

alpEy said:
@VortexA1

Do you know if it's possible to downgrade my BIOS? I don't have a flashback button or anyway of fixing it if it bricks, but I was thinking of downgrading to version 7C80v13 - Just before 11th gen was supported by my mobo. Maybe it will do something spectacular...who knows!

Should be able to reflash to an older bios same way as you updated it.

VortexA1 · 3 Oct 2022 at 00:33

alpEy said:
I left it for 10 minutes, unfortunately now change. Just stuck with the VGA debug light on.

GPU Logo lights up & the fans still spin…

Sorry to hear it didn't work mate. Keep us posted on how you get on with sorting this issue.