4K graphics problems with Intel NUC11 with Ubuntu 20.04 LTS

Solution 1:

I have exactly the same issue and I have to register an account in AU just to add this answer.

My system is also NUC11 i7. My initial installation was Fedora and I got the same problem of random disconnects in HDMI connection when working at 4k/60hz.

I think the problem has something to do with memory installation.

The problem persists with the following tries:

• Replacing Fedora with Ubuntu
• Upgrading BIOS to the latest version (041 as this is written)
• Using USB-C to either HDMI or DP, both front and rear USB-C
• Trying different BIOS video memory configurations

But, interesting enough, after I added an additional RAM band, the problem got fixed automatically. My initial setup was just like yours with a single DIMM of 16G installed.

I wish could just add a comment to your question instead of having this added as an answer as I don't know if it really helps in your case.