Question My PC wont boot when GPU has PCle plugged in but works without it

[thepcexpert1121]

I've recently rebuilt my computer and kept my old graphics card. It has a intel i7 9700k, 32 gig ripjaw ram, mpg z390 gaming edge ac motherboard a liquid corsair cpu cooler and then my old gpu. I can plug my gpu into the motherbaord and it lights up on boot, but when i plug my PCle cables in the pc wont even boot, not for a second even. For some reason it boots when i plug two VGA into psu and only one into gpu but not both. It worked before I switched it to my new build and should be camptiuble. Ive tried using different cables and still nothing. Any help??

 

[DSzymborski]

I've recently rebuilt my computer and kept my old graphics card. It has a intel i7 9700k, 32 gig ripjaw ram, mpg z390 gaming edge ac motherboard a liquid corsair cpu cooler and then my old gpu. I can plug my gpu into the motherbaord and it lights up on boot, but when i plug my PCle cables in the pc wont even boot, not for a second even. For some reason it boots when i plug two VGA into psu and only one into gpu but not both. It worked before I switched it to my new build and should be camptiuble. Ive tried using different cables and still nothing. Any help??

What's the exact PSU and GPU? Let's not fly blind here; it's hard to answer a question about a PSU/GPU when you don't even tell us what either are. Also, what do you mean by "plug two VGA into PSU and only one into GPU but not both?" A much clearer explanation of what is going on would be helpful.

 

[thepcexpert1121]

The psu is corsair rm750 gold 80+ and the gpu is a msi 980. And what i mean by that is i plug the vga cables into the psu, but leave one with no end connection (so it is only connected on one end) and the other i plug into the gpu.

 

[DSzymborski]

The psu is corsair rm750 gold 80+ and the gpu is a msi 980. And what i mean by that is i plug the vga cables into the psu, but leave one with no end connection (so it is only connected on one end) and the other i plug into the gpu.

And is this the same PSU as the old build?

 

[thepcexpert1121]

No it is brand new.

 

[DSzymborski]

No it is brand new.

And you used the new modular cables?

 

[thepcexpert1121]

yes and I tried the old ones

 

[DSzymborski]

yes and I tried the old ones

Oof, do not try the old ones. The pinouts in modular cables are not universal on the side that connects to the PSU and there's a high chance of destroying anything that's connected to a cable with the wrong pinout. Did you try the new ones first?

If you did try the new ones first, do you have your old PSU to test?

 

[thepcexpert1121]

I tried the new ones first and it didn't work. Yes I have it but no difference in results.