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I just turned it off and booted it back up with a macos test hd and ran the heaven gpu benchmark for 20mins without a hitch. This time as I monitored the p-bus voltage I didn't see it move from 12.7V at all.
When I quit the benchmark, I noticed a ghost of the istat menus drop down thing that I was using to watch the sensors. I double checked that the GPU was back at 0V so it seems to be related to switching from the GPU to the intel graphics. GMUX?
It's a bit of a pain to test for the ghosting on a monitor. If you still think that it's relevant to check I'll do the test.
Edit: during the OS test it does switch the graphics a few times so that may be why it kernel panics during that test after switching enough times to trigger some kind of malfunction.
The ghosting is only on the internal display. I ran the graphics test on loop for the internal graphics and 2 errors were logged but no kernel panic. I did have to reset the smc first as I was getting kernel panic every time ASD OS was loading.
If internal ghosting appears when external monitor is connected, then GPU is fine.
You must test with other LCD assembly.
If still the same, than could be GMUX issue.
Tested with a different display and there was no ghosting.
I tried to boot into ASD OS twice and had kernel panic both times so I booted into a test macos HD and ran the heaven benchmark for a while till it got nice and hot. Rebooted and loaded ASD OS successfully, ran it on loop and at some point it crashed with graphical glitches.
It runs just fine in macos and doesn't seem to mind stress test of the GPU. I did the same test with the heaven benchmark running while I made the CPU run really hard so the temp went over 100deg and left it doing that for more than 5 mins with no issues.
I ran the memory test with ASD EFI in the beginning, I forgot to mention that. Doesn't guarantee RAM is good but I think it's probably CPU. Do you think there is any point trying to put some flux under the CPU and hit it with hot air?
Use gfxcardstatus to switch the graphics and be sure if board fails only under iGPU, or discrete mode.
Still gives problems under normal use, after U8900 has been changed?