I have the AMD Framework 13 and I want to have it output video on my Gigabyte M32U monitor at 4k 144hz via a Thunderbolt/USB4 connection. The problem is that I’ve only been able to get 4k 60hz. I’m able to get the refresh rate I want using the DisplayPort Expansion Card, but I’d like to avoid using the DP cable because this monitor has a built-in KVM that is only accessible with USB-C.
At first I thought that this was a problem with my USB-C cable. But I tested the same cable and monitor with a different Framework laptop (an Intel 13th gen) and it was able to output 4k 120hz instead of 60hz. Also, I tried every compatible port on both laptops and got the same result.
I know that unlike the Intel variants, the AMD Framework doesn’t support Thunderbolt. It supports USB4. So maybe that is the root of the problem. Has anyone else with the AMD Framework 13 been able to get high refresh rates from a Thunderbolt/USB4 cable? If so what cable do you have?
What you’re doing when you connect a type C cable to this monitor is using a feature called “DP Alt mode”. It’s negotiated by the PD controller in Framework laptops and is described as part of the USB-C standards. Using the DP cable and the DP card will both use DP-alt mode from the laptop’s perspective.
However the monitor might not advertise the same features in the EDID depending upon which port you connect to it.
Have you tried to turn on/off DSC? This seems like the most likely reason that you can/can’t get the high refresh rates. You probably need DSC enabled to get the high refresh rate.
The bandwidth will be limited in DP alt mode and so if you can’t properly negotiate DSC for whatever reason you’ll be limited.
If you are using Windows, have you already updated to the latest BIOS and driver bundle? If not; do that.
If you’re using Linux, maybe you should try a newer kernel like the one that comes with Ubuntu 24.04 or Fedora 40 to see if it improves. You can very easily boot a USB stick with either as a data point.
Is DSC a setting I can change on the laptop or the monitor? When I tried to get 144hz from the Intel framework, the picture was grainier. I only got a clear picture when I reduced to 120hz. That tells me that compression must be turned on already, at least for that laptop. For the AMD Framework, I just see an option for 60hz until I reduce the resolution.
I am going to try it out with more Linux distros next. Previously I have been testing the AMD laptop on Fedora 39, and the Intel laptop was running Ubuntu 22.04.
Artifacts auch as that are very unlikely to be caused by DSC. And more likely caused by other options GPU drivers might employ to keep bandwidth down.
When connecting with the M32U via USB-C you are likely getting only half a DP connection because the rest is used for USB3 (which you can possibly downgrade to USB2 + full DP bandwidth in the OSD).
What the monitor can still do with only half the bandwidth is down to the monitor because reaching 4K144 with that seems very tight.
Comparing with a different host makes only sense if you see the actual settings being used. Like active resolution, color depth etc. Otherwise there are a lot of things that might be happening where one driver might flip rarely used and quality-degrading switches to still achieve the other chosen settings, while another might not want to do that automatically.
A lot of this can should also be shown in the monitors OSD.
Finally got it working! There is a setting on the M32U called “Type C Compatibility” that I had to turn off. Now I’m getting 4k 144hz on both Intel and AMD through the USB-C cable.