Big Sur random screen freezes with green lines then restart

[elgipsy]

XMP = overclocked RAM.

That's true but I have that enabled on all computers I have and never faced an issue, it's even in the opencore installation guide.

So far no issue when using Windows

 

[UtterDisbelief]

There it is, I've removed the ID's

As far as I can see you are using a headless / compute-only Fake iGPU ID (0x3E920003).

That could be your problem... ?

 

[elgipsy]

@UtterDisbelief

Not sure I'm following here...

As per dortania guide:

AAPL,ig-platform-id	Comment
07009B3E	Used when the Desktop iGPU is used to drive a display
00009B3E	Alternative to 07009B3E if it doesn't work
0300C89B	Used when the Desktop iGPU is only used for computing tasks and doesn't drive a display

and I'm using the 1st one, is 07009B3E a wrong value?

 

[pastrychef]

That's true but I have that enabled on all computers I have and never faced an issue, it's even in the opencore installation guide.

So far no issue when using Windows

If it's stable in Windows, I think we can assume it's a macOS thing...

 

[UtterDisbelief]

@UtterDisbelief

Not sure I'm following here...

As per dortania guide:

AAPL,ig-platform-id	Comment
07009B3E	Used when the Desktop iGPU is used to drive a display
00009B3E	Alternative to 07009B3E if it doesn't work
0300C89B	Used when the Desktop iGPU is only used for computing tasks and doesn't drive a display

and I'm using the 1st one, is 07009B3E a wrong value?

Apologies. My mistake. Base64 clearly not my strong point.

 

[UtterDisbelief]

Okay. So if all fine under Windows then it's macOS configuration.

Still on the display tack, I see you are using iMac20,2 ... Is there a model with that sys-def that uses the iGPU?

My eyesight is a bit dodgy at present but I can't see one. So why not try a different sys-def (while not connected to the Internet so that Apple don't lock your ID etc.) ?

I understand you might think you need iMac20,2 because of your CPU, but to test graphics go back a little and test others.

If this produces the same results I still lean towards what @pastrychef said about XMP and memory.

 

[elgipsy]

Okay. So if all fine under Windows then it's macOS configuration.

Still on the display tack, I see you are using iMac20,2 ... Is there a model with that sys-def that uses the iGPU?

My eyesight is a bit dodgy at present but I can't see one. So why not try a different sys-def (while not connected to the Internet so that Apple don't lock your ID etc.) ?

I understand you might think you need iMac20,2 because of your CPU, but to test graphics go back a little and test others.

If this produces the same results I still lean towards what @pastrychef said about XMP and memory.

actually no there are no 20,2 models without gpu, was planning to buy one but with these prices.... is there another system definition to use? Oh and wouldn't changing system definition require to get new ID's? I'm thinking about iMessage etc. as everything works currently, besides these freezes

 

[UtterDisbelief]

actually no there are no 20,2 models without gpu, was planning to buy one but with these prices.... is there another system definition to use? Oh and wouldn't changing system definition require to get new ID's? I'm thinking about iMessage etc. as everything works currently, besides these freezes

Yes, that's why I recommended disconnecting from the Internet whlle you test.

Two ways to approach this -

1) Create a USB boot-stick and make the changes there, not touching your installation.

2) Back-up your EFI and config.plist before you make any change, then just swap them back after testing, but before reconnecting to the Internet.

Don't try changing system-definition without taking this precaution.

As for recommendations to try, check what other people have used. Mac Mini's with UHD630 are recent - 2018. Granted the CPU is a mis-match, but that's not why we are testing. It's your graphics issue we want to nail.

Personally I run a Z490 with an i5-10600K and use iMac18,3. This is not a guarantee for your own PC, but certainly works here as I've done more testing than is heathy.

 

[elgipsy]

Yes, that's why I recommended disconnecting from the Internet whlle you test.

Two ways to approach this -

1) Create a USB boot-stick and make the changes there, not touching your installation.

2) Back-up your EFI and config.plist before you make any change, then just swap them back after testing, but before reconnecting to the Internet.

Don't try changing system-definition without taking this precaution.

As for recommendations to try, check what other people have used. Mac Mini's with UHD630 are recent - 2018. Granted the CPU is a mis-match, but that's not why we are testing. It's your graphics issue we want to nail.

Personally I run a Z490 with an i5-10600K and use iMac18,3. This is not a guarantee for your own PC, but certainly works here as I've done more testing than is heathy.

Hi there,

I had another freeze this morning but this time with red lines for a change

I went with the 1st option and made a boot stick emulating a Macmini8,1 and used that to boot with no internet and so far (about 2 hours) there hasn’t been any freezes and the I9 is correctly reported when looking at “about this mac”

If I am to stay with Macmini, how can I change the ID’s without messing up iservices and so on? Should I sign out of iMessage and AppleID before booting with the new IDs?

I should first check if the serial is ok to use though.

Then if I finally get a gpu one day, can I revert to iMac20,2 with its IDs?

Thanks a million

 

[pastrychef]

Hi there,

I had another freeze this morning but this time with red lines for a change

I went with the 1st option and made a boot stick emulating a Macmini8,1 and used that to boot with no internet and so far (about 2 hours) there hasn’t been any freezes and the I9 is correctly reported when looking at “about this mac”

If I am to stay with Macmini, how can I change the ID’s without messing up iservices and so on? Should I sign out of iMessage and AppleID before booting with the new IDs?

I should first check if the serial is ok to use though.

Then if I finally get a gpu one day, can I revert to iMac20,2 with its IDs?

Thanks a million

Check that the generated serial is clean.
If yes, start using the new system definition and boot in to macOS.
Log in to iCloud.
Go to System Preferences > Apple ID.
Look for your old iMac20,1 system and delete it from your account.