I’ve written loads about running Debian on the Microsoft Surface range of computers (tl;dr: it works really well), and also about my tribulations trying to find a working combination of Surface and two 4k monitors.
I gave up my hope of trying to get two monitors running at 60 Hz, and instead ran them both at 30 Hz, using the older clamp-style dock for a Microsoft Surface Pro 6. I didn’t notice a difference using 30 Hz rather than 60 Hz, and all was good. I never got the new-style dock to work reliably.
Surface Pro 6 and two 4k monitors was unreliable
While this has been a great set-up for a while, I’ve increasing found that the Surface Pro 6 was fine on its own (i.e. when undocked), but struggled occasionally when also running two 4k monitors. It would freeze for a minute or two before recovering, or else lock up, requiring a forced reboot.
I have not managed to track down exactly what caused it, but it would typically be when I was working on a document with lots of tracked changes, or was on a video call, and then did something else like loading my email client, or searching my email archive. So nothing unusual, and common enough that it was a problem.
It is a shame, as I like the Surface Pro 6 as a machine. But I use it for my job, and that kind of thing is just not good enough.
Surface Book 2 and two 4k monitors was never reliable
Fortunately, I found a Surface Book 2, 13", on eBay for £300. That’s a heck of a lot of computer for the price. It was in near-perfect condition, so I was pleased. And, unsurprisingly, that too runs Debian well.
But I had to fight with the new-style dock if I wanted two 4k monitors. I accepted I only would get (and only need) 30 Hz, but even that was a pain. I tried a combination of just the dock, and the dock for one monitor and a USB-C cable for the second. It made no difference: some times it work, and worked fine, other times it would take me 15 minutes of plugging and unplugging cables. Sometimes that would make one work, sometimes both at odd resolutions, and sometimes neither. Sometimes both.
Basically, far too unreliable to be usable.
Intel NUC and two 4k monitors has been fine so far
So I delved into a drawer, and found an Intel NUC that I bought for a project a couple of years back. I installed Debian, plugged in the two monitors (one micro/mini? HDMI, the other DisplayPort), and off I went. Not once has it screwed up the monitors.
It’s a noisier machine than I would like. Not terrible, by any means, but the constant noise of a fan is sub-optimal. I could probably experiment with fan control software, but I presume (ignorantly?) that the fan runs for a reason.
But I’ve had no problems with video calls (in Brave), and no issues or lock-ups when opening documents or using email at the same time. So, so far, so good.