Having a really weird issue between 3 machines, and I can't seem to get my head round it, other than deciding that one has a GPU fault.
I'm processing 8K red files in resolve with noise reduction, basic levels correction and some sharpening and exporting to ProRes 422HQ. These files are stored on numerous gtech raids we have. We've re-linked from the Red media that was assembled on set, to a previously exported proxy file, and now again to the graded/noise reduced high quality files.
Using Postlab (which is absolutely brilliant), we are working on the footage across 3 different machines and 3 different locations (current climate). A 2020 Mac Pro with a really high spec, a 2013 Mac Pro with a mid spec, and a 2017 MacBook Pro which is max spec. On the MacBook Pro ONLY, there is some weird green noise in the very darkest parts of the image which looks like luma noise. When you apply a curves adjustment to it, you can remove it, but some very minor detail is lost. The luma noise is still there when you export a file, whether its ProRes or H264/5.
Using the Mac Pro 2020 and Mac Pro 2013, the noise isn't there at all. It doesn't appear on the UI window, or on the video output, either when you use the XDR display or a Blackmagic Ultrastudio and a consumer grade 4K TV. Crucially, it doesn't appear when you export anything from the timeline either.
Normally it wouldn't be an issue, as all the mastered outputs would come from the Mac Pro 2020, but given current climate and working from home, I need some solution for getting the MacBook Pro in a position to export finished files.
Anyone have any ideas, or does it sound like the MacBook Pro has a faulty GPU? The added puzzler to this, is that the MacBook Pro also has an eGPU connected with a Radeon 64 inside, and this still displays the noise....
Have you checked the exports on other machines or the Macbook only? If it happens only on the Macbook display then the GPU is probably going. If the eGPU chassis has a place to connect a display you could also test if it's happening through that.