GPU not found - Mac Pro (2013)

I will try that.

I have noticed that when I leave it on for some time, shut it down (by long-pressing the power button) and turning it back on, it will show video output again (Not sure if that would work 100% of the time).

.. I keep fearing that it might be something similar to the xbox 360's red ring of death soldering issues, where it could be temporarily fixed by wrapping it in a towel, making it heat up for a while and it would work fine for a few days ..

Thanks.

Oh, that is odd.. I know it is an old computer, but I hoped it would last longer than this.

I'll have to go to an Apple store to see what the solution to this might be..

Just wondering, do you know how much it costs (at apple or authorized specialist) to replace the pair of D300 GPUs? I've gone through eBay but the prices are just insane (~$1,350 for both cards).

Oh, I was really hoping that it wasn't a GPU/Hardware issue, that's an expensive fix. :/

In your experience, is it odd that the Apple Diagnostics tool doesn't return any errors?

That is unfortunate.. and yeah, I was thinking that to run the diagnostic test, the display needs to be on anyway (working as intended), so it will never catch the error.

Thanks for your answers!