Pocket 3 - external monitor

I’ve had my Pocket 3 i7 for a month now and I’m loving it. I’ve never booted it into Windows; I put Mint 21.2 Edge onto it the day it arrived. It’s running the 6.2 kernel and everything works fine except the fingerprint reader. Well, “everything works fine” except …

I have a 4K Samsung monitor which is also used by my Mac Mini when I’m making music, and was used for years by the Pocket 3’s predecessor, a seven year old Dell XPS13. Neither of the other two devices had any difficulty driving the monitor and, indeed, the Pocket 3 drives it without issue at full resolution and 60Hz. But connecting the monitor, either through the HDMI socket or from a hub connected to the USB-C port, immediately slows the Pocket 3 to a crawl.

The performance hit is so severe I have to run the 4K monitor at a lower resolution to be able to do anything. And that performance issue is there even when the monitors go to sleep. I often run a video transcoding task overnight, and was initially impressed by the Pocket 3’s performance; it completed a run in 60% of the time taken by the Dell (also i7 and 16GB). However, with the external monitor connected, it takes 200% of the time, despite both screens being asleep for 98% of the process.

That’s the situation. I have some questions.

  1. Can another user advise whether this performance hit exists under Windows or under a different Linux distro?
  2. Is it worth trying a USB-C to HDMI cable, or is this issue going to persist regardless of the connector?
  3. Are there any known mitigations or workarounds, apart from lowering the external monitor resolution even further?

Many thanks,


I’ve discovered that running the external monitor at 30Hz is a significant improvement, enough to type in this forum without appreciable lag, for example. This is perhaps not the perfect solution though, and I’m still interested in responses to the three questions above.

While I have a GPD Win Mini and og Win Max, I recall a newer kernel on my distros (mainly Fedora, Fedora-based and Arch for tweak testing) helping a lot with monitor output.
As of writing, Fedora is currently on the 6.6.9 kernel, so I’m thinking the 6.2 kernel may be a bit old.
Does your Mint install offer any kernel updates through the built-in updater? If not, we may have to use mainline to get to a newer kernel in the 6.6.x series.
Here’s more info about that tool: GitHub - bkw777/mainline: Install mainline kernel packages from kernel.ubuntu.com

Thank you @s31bz … I’ll investigate that. I know Mint 21.3 will have a more recent kernel, and presumably the Edge release will push that even further. But if it doesn’t offer a 6.6 kernel I’m no stranger to updating the kernel separately.

I appreciate your help.

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I’m going to mark this post as solved (if that’s a thing here), and confess to being an idiot.

Today I updated to Mint 21.3, looking forward to seeing whether Wayland would address the external monitor lag issue. After installation I knew there would be a Wayland extension on the login screen, but couldn’t initially find it. Then I discovered the option is the round “mountain” icon to the right of my user name: I’d always assumed that was decorative. What’s more, when I clicked it, it showed not two, but three, options, and the one currently selected was “Softtware renderer”.

After selecting the alternative (which I assume means the Intel Iris chip), the external monitor runs 4K@60Hz without any lag or overheating. In fact the GPD Pocket 3 is now running 5℃ cooler away from my desk, and a whopping 10℃ cooler with the external monitor plugged in. Problem solved.

Wayland, incidentally, works fine. But the Display widget offers no way to rotate screens (and the internal screen needs to be rotated), and the taskbar is on the secondary external monitor. I’ll dig into these when I have time; it would be nice to have reliable Wayland rendering.

Thanks for the input on this issue. Discovering the root cause has been embarrassing, but at least the issue is resolved.