PC won’t boot after upgrade

starmanwarz · 28 May 2023 at 15:36

I installed my new 5800X3D, 7900XT and 32GB of RAM to my existing system (3700X, 5700XT, 16GB RAM, Corsair RM750X PSU) and my PC won’t boot.

So far I had my 5700XT connected with 1x8 pin cable which splits to 2x8 pins and it was working fine.

The 7900XT needs 3x 8pins and because I only had 2 I got one from my previous Seasonic PSU. I connected all 3 and nothing works.

After many hours of troubleshooting I discovered that when I have more than 1 cable connected to the GPU the PC won’t boot. I tried 3 different cables and 3 different PSU ports and the result is the same.

Now I tried booting with my old GPU, plugged it the way it was before, PC fans turn on but the GPU won’t.

Did I fry my PSU and possibly both my GPUs? Is there anything else I can try?

starmanwarz · 28 May 2023 at 16:41

Journey said:
Did you update your motherboard BIOS before swapping the CPU's?

Yes I updated to the latest version.

mickyflinn said:
You should never connect cables from a different psu without checking they are compatible, you may have broke your 7900xt.

Can you test the 7900xt in a different PC ?

I shouldn’t have used the cable

I can’t test the 7900 due to insufficient PSU but I am testing the 5700xt at a friends PC.

LuckyBenski said:
Have you confirmed your motherboard is compatible with new CPU i.e. BIOS is updated?

Try the 5700XT to rule out the graphics card.

The 5700 won’t power on, no leds and no fans working, testing at a friends pc atm to see if it works.

starmanwarz · 28 May 2023 at 18:33

Journey said:
If that is the newer CWT version is has 2x 6+2 pin PCI-E cables, but with 4 connectors, so should be enough to run the 7900XT without issue. Where did you connect the third cable from the old Seasonic PSU to on the new Corsair PSU?

I did that and the leds on the 7900 turn on but not the fans. Also the PC doesn’t boot.

starmanwarz · 28 May 2023 at 19:11

Journey said:
Did you do that before you tried the Seasonic cables though?

I didn't.

So, the 5700Xt won't work in 2 different PC's. No leds, fans, nothing. I think I fried it.

On The 7900XT the leds are working, but not the fans. It also doesn't boot with 2 cables. I will have to either find a 3rd cable or get a new PSU.

The 5800X3D doesn't seem to be working either. I have updated the B450 Tomahawk Max to the latest BIOS, do I need to do something else?

I'm exhausted and very very sad atm, any other ideas?

starmanwarz · 28 May 2023 at 19:23

Journey said:
So you could have killed them then.

I guess all you can do is bench test the lot, with a known good PSU and GPU to see if anything else is dead. If you can't do that due to lack of parts etc. and you live close by I am happy to assist where I can.

I really appreciate it, but we are several thousand kilometers away!

starmanwarz · 28 May 2023 at 19:26

LuckyBenski said:
As a way of breaking down the problem and hopefully regaining some confidence, I'd start by rebuilding the PC as it was. You can then swap components one by one to see what works.

I did that, old GPU (5700XT) won't work, the rest are fine although having 2 sticks of my old RAM is giving me some problems for some reason so I only use one for now.

Basically it's old CPU/Mobo/RAM and a 970 GPU which I got from a friend. Unfortunately I can't test the 7900XT on his system. I did test the 5700XT though and it doesn't work.

starmanwarz · 28 May 2023 at 19:59

SkeeterUK said:
what slots are the ram in?

2 and 4

starmanwarz · 28 May 2023 at 20:09

Is it a good sign that the leds on the 7900Xt are working or not? Could it still be fried?

starmanwarz · 29 May 2023 at 12:54

Yes I did reset cmos. Installed the old CPU and reset bios to default settings. I have the latest bios version.

New CPU won't boot at all.

starmanwarz · 29 May 2023 at 16:34

Managed to boot the PC with the new CPU and RAM and they are working fine. I think a restore to defaults in the BIOS did the trick.

starmanwarz · 29 May 2023 at 18:34

freddie64 said:
What about your GPU's (5700XT & 7900XT), are they working ok now?

Unfortunately no.

The 5700XT is probably dead, tested it in 2 PC's, no leds and I get a VGA error on my motherboard

The 7900XT is probably dead as well, although the leds are working. Also VGA error on my motherboard. It is connected with 2x8 pins though (1 splits to 2x8pins) and not 3. I am waiting a new PSU to give it another go.

starmanwarz · 30 May 2023 at 14:36

freddie64 said:
Hope the new PSU gets you up and running.

What PSU did you go for?

Corsair RM1000X, should come with plenty of cables. The RM750X only had 2 PCIE cables which is why I mixed and matched and possibly fried 2 GPU's

I'm really curious to see if the 7900Xt works with the new PSU or not. Also have a 4080 arriving tomorrow, if the 7900 works then the 4080 goes back. I really need my PC up and running by Friday for Diablo 4. Damn game is costing me a fortune.

starmanwarz · 7 Jun 2023 at 10:49

mickyflinn said:
@starmanwarz did you get your pc up and running?

I did, yes. Although I fried both the 7900XT and 5700XT

starmanwarz · 7 Jun 2023 at 11:30

mickyflinn said:
Unlucky That a real shame.

How's the 4080 performance?

It's great but the 7900XT was a much better VFM, especially because I got it for cheap.

Very impressed with low temps and low power draw! It's very quiet too.