Max refresh rate for Intel Iris Xe on 1195G7 CPU

[SF_B]

I bought a used Dell XPS 13 9310 with the 1195G7 CPU and the corresponding Intel Iris Xe GPU.

My monitor supports 75Hz but connecting the laptop with the USB-C 3.1 (displayport alt mode) cable only let's me set 60Hz. There is no 75Hz option.

I used to connect a Macbook M2 and it worked with that cable with 75Hz.

I'd like to know if this GPU even supports 75Hz at the monitor's native resolution of 3840x1600. I'd say yes as the max resolution is 8k@60Hz so with lower resolutions higher refresh rates should be possible.

So why can't I set this refresh rate on this Dell or with this GPU? Latest Intel graphics driver is installed.

[SF_B]

Please find the SSU logs attached. I installed Windows 11 for this as the Linux SSU variant was just out of date and not really working.

[Mike_Intel]

Hello SF_B,

Thank you for the information provided.  

I will do further research on this matter and post the response on this thread once it is available.

If you have questions, please let us know. Thank you.

Best regards,

Michael L.

Intel Customer Support Technician

[SF_B]

Just to let you know. I tried overriding the edid information using the CRU (custom resolution utility) tool in Win11. It did not accept it. Instead the external monitor fell back to 3840x1600@30Hz. I tried the same on Linux by overriding the kernel command line using "drm.edid_firmware" but it didn't like it either and fell back to 640x480. Fun!

I'm beginning to think that the Apple GPU driver on the Macbook where it worked kind of figures out the correct setting by itself OR we have a bug in both, Windows and Linux, Intel GPU drivers when using Displayport Alt Mode (USB-C to Displayport cable worked fine, as written earlier).

Let me know if you have any clue. I'll probably sell both, the monitor and the Dell laptop in the near future.

[Ernesto_C_Intel1]

Hi SF_B, 

Thank for sharing your recent troubleshooting. I'm currently working to recreate the issue you've raised with Iris Xe Graphics to determine the root cause of why you can reach the resolution: 3840 x 1600 x 75 Hz. 

I'll provide you an update on my findings as soon as possible. 

Regards, 

Ernesto C. 

Intel Customer Support Engineer.

[Mike_Intel]

Hello SF_B,

I hope this message finds you well.

Upon further checking, the iGPU should be able to reach its preferred 3840x1600 @ 75 Hz

This is further evidence by the demonstration done by @MUC

Regarding your checking with CRU, while this is a 3rd party tool - it clearly shows that the bandwidth is being capped.

At this point, it would be best to contact your laptop manufacturer if the resolution being outputted via USB-C DisplayPort (DP Alt Mode) is capped to only 60 Hz. 

Thank you and have a great day.

Best regards,

Michael L.

Intel Customer Support Technician

[SF_B]

Hello Michael,

that's unfortunate. Why would Dell cap the bandwidth for DP alt mode when it works with regular Displayport.

Seems I'll be selling the laptop.

Have a good day, too!