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dksoutha

macrumors member
Original poster
Mar 5, 2012
35
1
2012 Mac Pro shows no video in MacOS, but it runs fine in Windows 10 from a separate NVME (a pair of 970 EVO PLUS 512GB on a Syba.) I can see the boot screen and can watch MacOS begin to load, but the screen goes black at the login screen. Issue persists after SMC reset and COM+OPT+P+R four chimes.

Any thoughts?

Thanks in advance

2012 cMP
Sapphire Pulse RX580 Mac Vid Cards
Monterey with latest OCLP
48GBs RAM
 

dksoutha

macrumors member
Original poster
Mar 5, 2012
35
1
Is agdpmod=pikera set?
Hey startergo, thanks for your reply. I don’t yet know how to check that, but I’ll Google the path to an answer. Just this second it looks like an OC setting, and if so please know that I am using a vanilla OCLP install via the latest release. No custom settings.

I’m curious: does MacOS draw more power than Windows 10 when using the 580? In my machine it always runs warmer in MacOS than Win10, and if my backplane was compromised by a suspected recent power surge then the extra draw from MacOS may explain the lost video?

I’ll dig deeper into the OC settings 👍
 

tsialex

Contributor
Jun 13, 2016
13,142
13,330
Test your MacPro + RX 580 combo with native Mojave, do not add OCLP complexity to your equation - too much variables.

You can also use High Sierra.
 

dksoutha

macrumors member
Original poster
Mar 5, 2012
35
1
Great question: it used to work wonderfully on my 4,1/5,1 Mac Pro, but after my house lost power briefly last week that machine started showing those symptoms. A few days ago I bought a few 5,1s from a local business and, after updating the BootROM to the latest (144.....) via Mojave, I swapped the CPU and RAM to what I had in the 4,1/5,1 cMP, put in the HDD with OCLP and my NVMEs containing Monterey and Win10 and still have those symptoms. The 4,1/5,1 stopped booting entirely after awhile, but now it boots again although it shows worse symptoms: Win10 video cuts out with each heavy demand on the GPU (tested with games and movies.) The 5,1 shows nothing on the MacOS side, though Win10 appears to run without issues.

For those who've noticed my other recent post, my two 4,1/5,1 Mac Pros appear to be damaged by a suspected power surge, and a 5,1 appears to be damaged by a power strip compromised by that surge (the cMP worked at first, then stopped doing anything at all soon after updating its BootROM. BootROM update was successful and it booted to Mojave, then died.) Replaced the power strip with a new UPS.

I have replaced the Sapphire with a XFX 580 and get the same behavior. I had a pixlas mod on both machines, but I think the connectors may be loose as I swapped that cable and connectors to the new PSU. I am now using a dual mini-6 pin to 8 pin connector and still get those behaviors, those less often. Using a Mac 5770 shows no negative behaviors.

I think tsialex suggested in another post on this site that a bad vid card can wreck a backplane? Perhaps my Sapphire, which was in the 4,1/5,1 during the power outage, was compromised and has now damaged one or more of the the 5,1 Mac Pros I bought recently?

I have swapped the CPU tray in the 5,1 and got the same behavior. I have swapped the RAM, too. Interestingly, when I boot to High Sierra on an old HDD I get no behaviors. Could this be pointing to a failing EVO Plus NVME?

Thanks for your time, everyone.
 

dksoutha

macrumors member
Original poster
Mar 5, 2012
35
1
Ran AHT on the 5,1 and the EFI/OS diagnostics on the 4,1/5,1 and the only error refers to a temp sensor on the 580 when installed in the 5,1.
 

dksoutha

macrumors member
Original poster
Mar 5, 2012
35
1
...and I get to wear the fool's cap: the problem was a faulty video cable. Please don't ask how long it took me to figure that out.
 
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