[SOLVED] Can a PSU work fine at low draw, but not turn on when thirstier GPU is plugged in?

[peterspex]

In the wake of the 30 series being released, I decided to go ahead and finally upgrade my graphics card (1050 Ti) to a Aorus GTX 1080. Small problem: It won't boot.
When the PCIe cables are connected, the only thing I get is my ram lights turning on.
If I unplug the PCIe cables from the GPU, it will boot, but display "Please power down and connect the PCIE power cables for this graphics card." The GPU will light up, and the indicator LEDs on the card tell me there's no power.
I have a i5-9600k and a 750w Rosewill 80 plus bronze psu. I've never had any power problems when my 1050 Ti was running, even at full power draw. Is this a faulty PSU?

 

[Darkbreeze]

WHICH Rosewill PSU model do you have? There are only three Rosewill "series" that are worth using, and those are the Quark, Capstone M and Tachyon series. If your PSU is not from any of those three model series, then it is very likely an incredibly mediocre or more probably, poor quality unit.

The fact is, 750w doesn't always mean 750w and not every "750w" unit is built equally, or even has remotely similar performance.

That's not to say that the power supply IS the problem, because it might not be, but let's start there.

If you put the 1050 ti back in, does it work then?

 

[peterspex]

WHICH Rosewill PSU model do you have? There are only three Rosewill "series" that are worth using, and those are the Quark, Capstone M and Tachyon series. If your PSU is not from any of those three model series, then it is very likely an incredibly mediocre or more probably, poor quality unit.

The fact is, 750w doesn't always mean 750w and not every "750w" unit is built equally, or even has remotely similar performance.

That's not to say that the power supply IS the problem, because it might not be, but let's start there.

If you put the 1050 ti back in, does it work then?

It's a HIVE-750. I bought someone's self-build a while ago, and just upgraded things as time went on, but this PSU was in the original build.

Yes, I put the 1050 Ti back in and it works perfectly again. I've never experienced any random power cycles or shutoffs.

 

[Darkbreeze]

Then I'd say you got a bad 1080, and this is EXACTLY why I ALWAYS tell people to NOT buy used graphics cards. It is a gamble, and it's usually one that's usually a very fickle roll of the dice as to whether it ends well or not.

 

[peterspex]

Then I'd say you got a bad 1080, and this is EXACTLY why I ALWAYS tell people to NOT buy used graphics cards. It is a gamble, and it's usually one that's usually a very fickle roll of the dice as to whether it ends well or not.

I was hoping that wasn't the answer ( I got it off FB marketplace with purchase protection, so if it does end up being faulty, I should have a full refund. I'll be testing it with a different psu tomorrow. Thanks for the help!

 

[Darkbreeze]

Yes, test it with another PSU, and ALSO if possible, test it in another machine entirely.

 

[peterspex]

Then I'd say you got a bad 1080, and this is EXACTLY why I ALWAYS tell people to NOT buy used graphics cards. It is a gamble, and it's usually one that's usually a very fickle roll of the dice as to whether it ends well or not.

Just to follow up, I hooked up a 650w PSU, and it booted up just fine! Guess it was the old PSU. I opened it up (before I knew not to) and got a decent amount of dust out, but it didn't fix the problem. Maybe the PCIe hookups were bad? Not sure, but I'm good with a new PSU, the old one was getting very old.

 

[Darkbreeze]

Good deal man. Much better than having to replace the graphics card.