Installed a new GPU, now PC wont start/loss of power

VSK933 · 18 May 2024 at 22:56

Hello
I have a 850w psu, b450 tomahawk mobo, 16gb ram, ryzen 7 5800x cpu and have swapped my 3070ti out for a 7900 xtx.

I ran DDU, swapped the cards and installed amd drivers and played a game for about 15 minutes and then the pc went black, started constantly turning on and off and after I held the power button down now if I turn it on the mouse, keyboard and display don't work or light up at all. The only things that work are fans, cpu cooler, gpu lights and the only thing I can see different is 1 fan has stopped spinning.

Any help welcome thanks

Gray2233 · 18 May 2024 at 22:57

What is the exact make and model of PSU?

VSK933 · 18 May 2024 at 22:59

Gray2233 said:
What is the exact make and model of PSU?

Seasonic focus 850w gx 850

freddie64 · 19 May 2024 at 09:15

Have you still got the 3070ti and if so does that work?

Are you using a anti-sag bracket?

Are you using 3 seperate power cables for the GPU?

VSK933 · 19 May 2024 at 09:26

freddie64 said:
Have you still got the 3070ti and if so does that work?

Are you using a anti-sag bracket?

Are you using 3 seperate power cables for the GPU?

I haven't had chance to plug the old GPU back in.

The 7900 came with a rod and l bracket style bracket which I have installed with the base resting on the bottom of the case and the arm supporting the gpu but not touching the fans.

I pressed the power button this morning and it tried to boot a few times then power came on with a black screen saying the memory overclock has failed but I haven't done anything further with it.

To my knowledge the ram isn't overclocked so not sure what to do with it

freddie64 · 19 May 2024 at 09:31

Maybe try CMOS reset?

pastymuncher · 19 May 2024 at 18:53

VSK933 said:
I pressed the power button this morning and it tried to boot a few times then power came on with a black screen saying the memory overclock has failed but I haven't done anything further with it.

A cmos battery that needs replacing can cause all sorts of weird messages and symptoms. As it's a B450 motherboard it's at least a couple of years old now so may be worth replacing the cmos battery to rule it out.

Also a 7900XTX is a big increase in power draw over a 3070ti so ideally you need to power it from seperate pci-e leads and not by the daisy chained connectors from a single lead.

siumatfung · 20 May 2024 at 11:32

I think you should only plug in the mobo gpu and nothing else and try booting and just incase the additional 4/8 pin mobo connector

Vinno · 27 May 2024 at 09:16

I'd try a CMOS reset before anything else.

ED209 · 27 May 2024 at 09:47

Have you made sure your bios is fully up to date?