PC do not boot if GPU is plugged in

[Kysis]

Hi guys,

I searched on this forum for a post that could help me and my little PC, and could not find one that matches my problems, so here it is.

So, 3 days ago I was playing GTA5 (with Spotify and Discord opened on side), I was on my 7th hour of gaming, and suddenly my PC shutted off, without a single error, BSOD or whatever. Tried to restart it after 10 or 15 minutes, but no sign of live (just the mobo LEDs that are constantly lightning).

 

The specs :

CPU : Ryzen3 3100

MB : Asus B450 Gaming Plus

GPU : Gigabyte 780Ti OC

PSU : Corsair CX650 (650W)

RAM : 2x8Go 3200MHz

OS : Windows 10 64bits

 

What I did until now :

- Tried to restart it 2 or 3 times, after completely disconnecting PSU and clear CMOS : no fans spinning, no bios appearing

- Moved the GPU on a different PCIe slot : no fans spinning, no bios appearing

- Disconnected the two 6+2 power cables of the GPU : no fans spinning, no bios appearing

- Dusted off the GPU card, applied new thermal paste on the GPU itself : no fans spinning, no bios appearing

- Tried another GPU (Gt440) I have in stock, on the PCIe slot I usually use : properly boots, the PC is back to life

 

I'm having an enormous headache right now as I don't know if the culprit is the GPU or the PSU, and with the actual state of the market, I would prefer to buy a new PSU rather than a new GPU card.

 

The card is going to be tested in another PC in the next few days, meanwhile any thoughts would be appreciated. Thanks in advance !

 

PS : and another little problem, with the Gt440 in place, if I try to pull just a little bit my headset cable (which is located next to the HDMI cable), the PC *sometimes* crashes and restarts right after.