MP 1,1-5,1 MacPro 5,1 w/ RX580 High Process Load Issue

[freedom42]

I have a MacPro 5,1 with a MacVideo Cards modified RX580 connected with a split power connection to the mainboard's +12v connectors. In short this setup has never caused the system to shutoff under high GPU processing load. But unique to using Topaz's Photo AI and Gigiapixel AI applications the system will black screen with all of the fans running 100% and the Xeons unresponsive. These Topaz apps are very GPU intensive, point in fact, though using the benchmark apps I have never been able to create a shutoff or this black screen problem.

Just before the system black screens I noticed that the MacPro's power supply is claiming to be supplying 35-36 amps at +12V or ~430 watts.

Note I tried an unmodified RX580 (yes I have an extra) which results in the same behavior. The system is using Martin's OpenCore configuration where the version of OpenCore does not appear to effect the resulting behavior.

Is this a software crash or is it an unexpected overcurrent situation?

 

[freedom42]

I have a MacPro 5,1 with a MacVideo Cards modified RX580 connected with a split power connection to the mainboard's +12v connectors. In short this setup has never caused the system to shutoff under high GPU processing load. But unique to using Topaz's Photo AI and Gigiapixel AI applications the system will black screen with all of the fans running 100% and the Xeons unresponsive. These Topaz apps are very GPU intensive, point in fact, though using the benchmark apps I have never been able to create a shutoff or this black screen problem.

Just before the system black screens I noticed that the MacPro's power supply is claiming to be supplying 35-36 amps at +12V or ~430 watts.

Note I tried an unmodified RX580 (yes I have an extra) which results in the same behavior. The system is using Martin's OpenCore configuration where the version of OpenCore does not appear to effect the resulting behavior.

Is this a software crash or is it an unexpected overcurrent situation?

Ran the same Topaz software with the same image with a cold machine and there was not a repeat of the black screen event. Which is why I'm now tending to think this is a thermal problem.

Another thought... While I have not seen the Northbridge diode temp move from a maximum of 77C, I wonder if the Northbridge is unhappy. Ordered new plastic rivets though the existing rivets are intact. But if I pull it apart to renew the thermal paste, likely it is best to just replace the rivets at the same time. Note the CPUs were replaced a few years ago and new paste was used at that time, thus I don't suspect it is the Xeons causing a problem.

 

[h9826790]

Just before the system black screens I noticed that the MacPro's power supply is claiming to be supplying 35-36 amps at +12V or ~430 watts.

If you want to know the actual power draw of the graphic card, you can check the actual current on PCIe slot + Aux A + Aux B.

All 3 power sources are 12V, e.g. 2.5A on PCIe slot, 5A on Aux A, another 4.5A on Aux B.

Then (2.5+5+4.5) x 12 = 144W

 

[freedom42]

If you want to know the actual power draw of the graphic card, you can check the actual current on PCIe slot + Aux A + Aux B.

All 3 power sources are 12V, e.g. 2.5A on PCIe slot, 5A on Aux A, another 4.5A on Aux B.

Then (2.5+5+4.5) x 12 = 144W

Perhaps I was lazy to document those numbers in this thread, but the numbers individually were under the limits that people speak to as well as the total number was reasonable as well. Which brings me back to either this is a annoying issue with Topaz's software and the MacOS 12.X libraries, or maybe the Northbridge is over temp. Though I never see the Northbridge temp over +77C and nominally is between 72 to 77C. But when I get the parts in hand I will replace the thermal transfer paste when I install new rivets.

If I'm not mistaken I'm using your configuration for OpenCore. And if so, thank you!