@damarrin
Sure there use the same driver installation blob but there are different HW architectures. I would be very suppressed if there are no differences in the driver.

So, I just played Minecraft for a while and it happened again. The PC froze. This time I had an ssh connection open the whole time and this was dead.
The Xorg log shows only this lines at the end. You can see the time difference.

Spoiler, click me

[ 59.125] (II) AMDGPU(0): Modeline "1280x800"x0.0 83.50 1280 1352 1480 1680 800 803 809 831 -hsync +vsync (49.7 kHz e)
[ 5691.334] (EE) client bug: timer event5 debounce: scheduled expiry is in the past (-0ms), your system is too slow

The journal gives this in the end (The pam messages are from the monitoring I did every second.):

Spoiler, click me

Mär 08 10:56:03 moritz sudo[52433]: alfred : TTY=pts/2 ; PWD=/home/alfred ; USER=root ; COMMAND=/usr/bin/cat /sys/kernel/debug/dri/0/amdgpu_pm_info
Mär 08 10:56:03 moritz sudo[52433]: pam_unix(sudo:session): session opened for user root by alfred(uid=0)
Mär 08 10:56:03 moritz sudo[52433]: pam_unix(sudo:session): session closed for user root
Mär 08 10:56:04 moritz sudo[52442]: alfred : TTY=pts/2 ; PWD=/home/alfred ; USER=root ; COMMAND=/usr/bin/cat /sys/kernel/debug/dri/0/amdgpu_pm_info
Mär 08 10:56:04 moritz sudo[52442]: pam_unix(sudo:session): session opened for user root by alfred(uid=0)
Mär 08 10:56:04 moritz sudo[52442]: pam_unix(sudo:session): session closed for user root
Mär 08 10:56:05 moritz sudo[52452]: alfred : TTY=pts/2 ; PWD=/home/alfred ; USER=root ; COMMAND=/usr/bin/cat /sys/kernel/debug/dri/0/amdgpu_pm_info
Mär 08 10:56:05 moritz sudo[52452]: pam_unix(sudo:session): session opened for user root by alfred(uid=0)
Mär 08 10:56:05 moritz sudo[52452]: pam_unix(sudo:session): session closed for user root
Mär 08 10:56:06 moritz sudo[52461]: alfred : TTY=pts/2 ; PWD=/home/alfred ; USER=root ; COMMAND=/usr/bin/cat /sys/kernel/debug/dri/0/amdgpu_pm_info
Mär 08 10:56:06 moritz sudo[52461]: pam_unix(sudo:session): session opened for user root by alfred(uid=0)
Mär 08 10:56:06 moritz sudo[52461]: pam_unix(sudo:session): session closed for user root
Mär 08 10:56:07 moritz sudo[52470]: alfred : TTY=pts/2 ; PWD=/home/alfred ; USER=root ; COMMAND=/usr/bin/cat /sys/kernel/debug/dri/0/amdgpu_pm_info
Mär 08 10:56:07 moritz sudo[52470]: pam_unix(sudo:session): session opened for user root by alfred(uid=0)
Mär 08 10:56:07 moritz sudo[52470]: pam_unix(sudo:session): session closed for user root
-- Reboot --
Mär 08 10:58:21 moritz kernel: Linux version 5.5.8-1-MANJARO (builder@216fb1516504) (gcc version 9.2.1 20200130 (Arch Linux 9.2.1+20200130-2)) #1 SMP PREEMPT Thu Mar 5 20:29:51 UTC 2020
Mär 08 10:58:21 moritz kernel: Command line: BOOT_IMAGE=/vmlinuz-5.5-x86_64 root=UUID=7f7d3134-e671-4bf4-b00c-dac4ecf90413 rw oops=panic udev.log_priority=3 audit=0 amdgpu.ppfeaturemask=0xffffffff amdgpu.vm_debug=1 amdgpu.vm_fault_stop=2 amdgpu.gpu_recovery=1 processor.max_cstate=3 rcu_nocbs=all

I think this has cost enough of mine (and your) time already. I spend at least 30 hours on this by now and every time I thinks its working, it happens again. I will order a RTX 2060 Super today.
Putting some time into finding a solution for a problem is not an issue if there are at least some hints whats going on. But this situation is not what I have in mind when I want to play a game after working the whole day writing software.
(Anyone wants to buy a Vega 56 Shapire Pulse? :)

Thank you all for your support
Dax

Well, the purpose of changing the gfx card is to see if your computer continues hanging with a different card and if it doesn’t you’ll know the Vega is at fault and not something else.

That was how I understood you. Of cause there could be other problems with the PC (mainboard, power supply etc.) but the freezing is related to having some OpenGL application running. It never happened when I watch youtube or read mails or using Fierfox, unless a game is running in the background. In addition to that, there are a lot of people reporting same problems with Vega and Navi cards.
The order for a new graphic card got out 10 minutes ago. (Because it is send to my mother I will get it next Saturday.)
It is not because I want a NVidia card. When the Vega is working it does a great job and I'm actually happy with the performance and even the fan is barley noticeable.
If its not the GPU, then I buy other components. At the end I might have 3 PC here and only one is working :'(
The reason I chose an AMD GPU is that I don't like NVidias politics but as I sad in my first post, I might end up not using a PC for games anymore at all. I'm not at this point just yet.

Dax

I buy only Asus graphics cards and motherboards after decades of building my personal computers. Asus has good product quality and 3 years warranty here. Sapphire products have 2 years warranty. You use Vulkan with DXVK and many play windows games mostly.

Years ago I had an ASUS Mainboard which had some problems with the RAM. I think it was a Socket A board. The ASUS support was very kind and tried to help me but as far as I remember the problem could never be solved. I than tried MSI and since then MSI boards are the best way to go. Before ASUS only gigabyte was the best, so I thought.
The GPU cards manufactures I used so far are ELSA, ASUS, Gigabyte, MSI, Sapphire, Palit (there is still a GTX560TI on the shelf). The RTX 2060 Super I ordered is from Palit. (I will get it today.)
The MSI GTX 970 has a bug in the fan control which is known by MSI but has never been fixed. From time to time one fan stops spinning and the the other goes up to full speed. I never closed the casing of my last PC because I had to give the not spinning fan a short nudge and it starts spinning again.

What I'm saying, the manufacture is not the way someone should select PC components. From time to time every company produces a bad component. Checking tests is the best way I know. Of cause not all tests are without bias and some are very bad. A while ago I found the youtube channel IgorsLab (in German). He uses very high end equipment to test HW. Never found someone who actual measured the 10ms peek power consumption of GPU's, which could be a problem for the power supply.
(No I'm not starting writing about power supplies, this will end up in a short novel:)

I don't think the problem I have with the Vega is related to Sapphire but to AMD. But it would be interesting if there are manufactures who has this problem more likely. As I wrote, my PC freezes completely. That means the Linux kernel is not running anymore. Not sure a driver can actually so this. My hunch is, that the GPU is holding the DMA or an IRQ or makes some bad noise on the power so the CPU stops working.

Thanks for reading,
Dax

PS.
As soon has I have more information I will post this here. I'm might buy other components to build a 2nd PC for the Vega card to test this. Maybe this is not one problem but a combination of more then one.

PPS.
I'm working as a SW developer on embedded systems and yesterday I finally could build the test system to evaluate the new APU board we like to use in the next gen of our devices. Its an AMD R1605B APU with Vega graphic. First tests, using debian unstable, looks good. Hopefully this APU does not have the same problems I have. Our devices are running 24/7 in industrial production lines.

Just a short update.

Now the 2060 is in use for over 2 weeks and not a single freeze. I think its safe to say the Vega has a problem. If hardware or driver is still a question.

I'm working from home at the moment. My PC is running much longer than usual.