Fedora Workstation 34 Should Be Very Exciting With GNOME 40, PipeWire Default

[getaceres]

I have seen something like this before not at 4k but if it is this you display can be frame skiping or not in fact rendering at the HZ speed. I have had a 120Hz 1080p show up at 60Hz before and then appear to be back to normal 120Hz with HDMI and Display port on different machines with cable issues. I have also had it be mega wacky. Like Stable 120Hz with windows and unstable with Linux and the revserse Yes I have two HDMI cables here one behaves perfect 120Hz with windows total crap with Linux and another the gives perfect 120Hz with Linux yet gives total crap with windows. The negotiation method and error correction and tolerance methods are slightly different between Windows and Linux drivers result in some cables work fine with one OS and nothing else.

If you have a dud cable this can increase GPU processing load as GPU is doing resend this is partially worse with Intel graphics than AMD.

The fact you are not getting a clean 60Hz suggests cable trouble. If you have cable trouble the output results horrible scrolling/frame skipping ... can all be the result of the GPU being stubborn doing everything to attempt to get a image displayed on screen at any cost. So you might have a value that screen is running at 60hz when really only 20 frames a second is being rendered because of CRC failures.

By the way capable freesync/gsync monitors.

getaceres basically you mix of hardware ticks all the boxes for a really bad experience due to a defective cable. Please note this defective cable does not mean Windows cannot work right or Linux cannot work right. Its just depends on what the issue is in the cable if the Intel graphics will respond badly on windows or Linux. The fact that the monitor is freesync this can result in the monitor saying 60Hz but the real frames per second be some value less.

Fun part is the type of cable defects with capacitive issues in cables the display port/hdmi cable can come operating system selective if it causes issues or not as the pattern of transmission the driver generates down the cable if you have error or not.

It turns out you were right and the problem was with the hardware. Probably a combination of GPU and cable. I was trying with a mini-PC with a Intel Core i5-5257U processor and although it was fine on Windows I couldn't watch 4K videos in Youtube as they were constantly cut. In Linux even 1080p videos were skipping like crazy and this processor should be more than capable to do that, according to the official specifications. I guess supporting 4K 60Hz is not the same as being competent when it comes to managing it.
I returned it and I got another one with a Ryzen 7 Pro 2700U and the difference is HUGE. If you look at benchmarks, of course there is a difference between the processors. It's a different brand, range and generation but not so much as to explain going from an unbearable 4K experience in Linux to a perfect one. Now with this machine, connected by HDMI 2.0 with the provided cable, every distribution I've tried always gets 4K 60Hz and the experience is as smooth as windows if not more, even with fractional scaling. After enabling WebRender and video acceleration in Firefox, I also get a better experience watching 4K videos in Youtube than I get in Windows. So I guess the difference here is between the Intel driver (good in Windows, not so much in Linux) and the Radeon driver (pretty good in both of them).
It's a shame that Linux does not support HDR yet as with this machine I could use it connected to my main TV and use it as a media center. I guess for that I must continue with Windows.

[oiaohm]

So I guess the difference here is between the Intel driver (good in Windows, not so much in Linux) and the Radeon driver (pretty good in both of them).

There are a few differences. Intel iGPU signal strength down HDMI, Display port... depend on the driver so this now comes OS dependant. Yes too strong of signal down a cable can cause interface and too weak the signal does not make it intact either way things are going to play up. AMD hardware will dynamically adjust independent of the driver in use. I have had the fun one with iGPU where the bios is blank and windows and Linux both show video out this is this signal strength thing.

AMD GPU even in their CPU is more tolerate to bad cables as in cables a Intel iGPU is not even going to give a picture with AMD GPU some of the cables will able to use and act like everything is good.

I have not played with the Core i5-5257U my self to know if it should handle 4K videos in youtube. Yes a broken/incompadible cable causing resends under windows/Linux with Intel iGPU even if you get the correct HZ can reduce the amount of processing power the Intel iGPU has. So accelerated decoding of 4K is something I would also expect to see failure with dead cable that is pretending to work with a Intel iGPU as well.

Please note Nvidia also uses dynamic adjust in GPU of signal strength.

How I learnt about the signal strength one with intel is I had a 10 meter cable off a Windows XP machine to a screen I updated the Intel drivers and now it had no picture then I downgraded the drivers and the picture was back. So fun of Intel. So having a good driver with Windows for now with Intel does not mean you will in future. Its something reviewers don't talk about you go Intel GPU your monitor cables are more of a issue. I am crossing fingers that Intel with the decanted GPU line finally get a decent dynamic signal power system.

As you have seen give Linux or Windows correctly working hardware 4K is usable. If it not you have hardware trouble.

Thing to remember Intel official specifications are basically ideal conditions in past generations that you will be using perfectly good cables and perfectly good monitor with no interference/signal issues. AMD and Nvidia specifications on what a GPU can do were more realistic as they would go the specifications have to work with a horrible cheap as chips cable just outside the specifications.