GPU causing PC to boot and operate slowly but only sometimes

[Jusberi]

I've been troubleshooting a problem where my PC would boot and operate slowly but only sometimes.

Slow boot and poor performance would start the moment I would press the power button, monitor would stay blank for several seconds and then the motherboard (Prime Z590-A) ASUS logo would slowly load to my screen. And when entering BIOS it would be so sluggish that mouse navigation is not possible because there is a 2-3 second delay when moving mouse cursor. If I would continue to boot in this state programs and games would take ages to load and the FPS in games would be horrendously poor. And if I would reboot there is a chance that it would boot just fast and normally and no problems whatsoever.

Because the problem extends to BIOS and loading ASUS logo it would certainly be a hardware issue. I replaced RAM's to brand new and tried with different hard drive. My friend gave me a tip that I could remove my RX5700XT and use integrated graphics. I tried that and sure enough the boot was lightning fast every single time and it worked just fine. So I tested my old AMD 6950 to see if the PCIe bus is somehow broken or bad settings on it, that was not the case as the 6950 was also booting fast and working just as expected. So in 99% certainty the problem would be the RX5700XT, right?

 

It has warranty left on it so I could return it but I am very curious to know what on earth could cause the GPU to be broken like that that it would cause problems but only some boots? Memory on it is somehow broken or what?

[Pixelfie]

Can you try clearing the CMOS? Are you sure you have the GPU in the correct PCIE slot (usually top)?

 

You can try RMA but they will probably just refund which is worth half a GPU in the current situation.

 

[Jusberi]

53 minutes ago, Pixelfie said:

Can you try clearing the CMOS? Are you sure you have the GPU in the correct PCIE slot (usually top)?

 

Does GPU placement really matter on my motherboard? To my understanding they are all the same, three PCIe 4.0 slots x16

I have it on the second one, no chance to fit it to the first one because there is watercooling stuff on the way.

And even if there would be any difference, how could it be possible to restrict performance to very poor level but only on some startups?