Display Blackout Problem

[MrMagicMadMax]

I ran into an issue yesterday with my 5,1. While using it for about 2,5 hours to watch some YouTube and select some RAW photos in Finder and later editing them in Lightroom, the center Display randomly turned black with only a cursor on it for about a second and then all three turned completely black and I'm logged out and thrown to the login screen. This happened like 4 times or so.
Unfortunately I changed quiet a few things since friday:
- Installed additional 64GB of RAM (128GB total)
- Upgraded bootrom to 140.0.0.0.0
- Upgraded El Capitan to High Sierra
- Upgraded to the latest Web Driver
- Installed the GT 120 in Slot 2 (GTX 980 still in Slot 1)
- Moved one Display from the GTX 980 to the GT 120
- Moved my Install from an AHCI SM951 to a NVMe 2TB 970 EVO

I already used the 128GB RAM and Bootrom 140.0.0.0.0 with El Capitan on the old SSD for a day and had no problems.
I also had High Sierra from the HDD running for hours to clone the SSD with the current GPU configuration, RAM and Bootrom with no problems but I wasn't doing anything except using Disk Utility to clone the drive.

 

[TC!!]

I ran into an issue yesterday with my 5,1. While using it for about 2,5 hours to watch some YouTube and select some RAW photos in Finder and later editing them in Lightroom, the center Display randomly turned black with only a cursor on it for about a second and then all three turned completely black and I'm logged out and thrown to the login screen. This happened like 4 times or so.
Unfortunately I changed quiet a few things since friday:
- Installed additional 64GB of RAM (128GB total)
- Upgraded bootrom to 140.0.0.0.0
- Upgraded El Capitan to High Sierra
- Upgraded to the latest Web Driver
- Installed the GT 120 in Slot 2 (GTX 980 still in Slot 1)
- Moved one Display from the GTX 980 to the GT 120
- Moved my Install from an AHCI SM951 to a NVMe 2TB 970 EVO

I already used the 128GB RAM and Bootrom 140.0.0.0.0 with El Capitan on the old SSD for a day and had no problems.
I also had High Sierra from the HDD running for hours to clone the SSD with the current GPU configuration, RAM and Bootrom with no problems but I wasn't doing anything except using Disk Utility to clone the drive.

I used to have lots of problems with being logged out in High Sierra running 2x5770 cards. I would see lots of graphical issues with areas shown as red, for example the whole Apple Mail window, clicking on one of them would cause a redraw and they'd show correctly. I haven't seen anything like this since moving to an RX580 and Mojave. I'm having other problems but that logging out issue was definitely linked to High Sierra for myself.

Edit: Also the issue of being logged out was almost always linked to me using more than 1 app in full screen mode.

 

[MrMagicMadMax]

Today my power cable arrived and I replaced the GTX 980 with the RX 580 and also upgraded to Mojave. I'll have to test it more, but so far I didn't experience any random logouts. The only problem is, that the Mac Pro shuts off completely when the RX 580 is put under load because I use a mini 6-Pin to 8-Pin PCIe Power cable. A dual mini 6-Pin to 8-Pin is on it's way from China however.