Getting Moonlight streaming to work at 120hz using a Bazzite client

Hi team.

I've just set up a HTPC (TRIGKEY R7 6600H/660M/16GB/500GB) with Bazzite and having a great experience so far! Thank you for all your hard work on this OS. If I solve this issue I doubt I'll ever boot into the Windows partition again.

Now, I've setup this PC to mainly serve as a Moonlight streaming client from my main gaming PC to my living room, where I have a LG C3. As mentioned I've got a dual boot going with Windows, and setup Moonlight streaming clients identically on both OS. However, when trying to stream 4k@120hz HDR, I'm having a strange issue when running under Bazzite.

In the first attached picture, you can see while streaming under Windows 11 I have full 120 fps with no drops or other issues.

In the second attached picture, you can see while streaming under Bazzite Moonlight is capped somehow to only render at 60fps, with 50% (it does fluctuate a bit) attributed to be dropped due to "network jitter". Given the "frame queue delay" stat, I assume frames are only grabbed at 60fps and the network buffer is not consumed fast enough, leading to the drop being attributed as it is.

Under display settings I've set the resolution to 3840x2160@120. If I hop into desktop mode (gnome) and check the display settings there, it's all setup for 4k 120hz as well and seems to be working fine. If I run Moonlight under dektop mode I get the same issue.

I would love to get some input on what to try next and hear if anyone has run into any similar issue.

HikariKnight•1/6/25, 10:54 AM

Did you enable higher fps in moonlight settings?
I have never used higher than 60fps as my network setup can't handle it (can't believe the landlord wouldn't let me drill a hole to the basement for a cable to my server /s)

ScruffyOP•1/6/25, 10:58 AM

Yes both Windows and Bazzite clients are configured for 4k 120hz 150mbps. That configures the incoming 120hz video stream, which is coming in fine on both ends. Reading the stats in the screenshots, the client under Bazzite has an issue rendering it at that rate.

HikariKnight•1/6/25, 11:00 AM

Are you running moonlight through gamescope in desktop mode?

HikariKnight•1/6/25, 11:02 AM

Well it's not something I can even attempt to replicate due to my situation so I can't think of more than gamescope locking it to 60 for whatever reason.
Or there being a difference with the network driver or moonlight on Linux

ScruffyOP•1/6/25, 11:05 AM

I've tried:

Running it in Game mode (added Moonlight as a non-steam game in desktop mode, then switched over to Game mode and ran it)
Running it directly in Desktop mode (e.g. not via Steam)
Running it via Steam in Desktop mode

Only interesting observation is that rendering seems to cap at 60fps in Game mode and 50fps in Desktop mode.

ScruffyOP•1/6/25, 11:07 AM

Frame limit in performance overlay is at 120 fps default, and disabling frame limit changes nothing. Flipping "allow tearing" also doesn't change anything.

HikariKnight•1/6/25, 11:10 AM

Then I am unsure since I can't test this myself due to being forced to use powerline between my apartment and the basement where my server is so I'm capped at 720p@60

HHikariKnight Then I am unsure since I can't test this myself due to being forced to use power...

ScruffyOP•1/6/25, 11:17 AM

Yeah I’m very aware I’m pushing the limits of what’s possible here. Tomorrow I’ll get a cable that hopefully lets me get VRR going as well, then I’ll have achieved end game streaming setup

ScruffyOP•1/6/25, 11:33 AM

Some more data. Running 720p@120hz @ 150mbps and 1080p@120hz @150mbps seems to cap out at around 80fps

ScruffyOP•1/6/25, 11:34 AM

Ah. Adding the performance overlay I can now see my GPU sitting at 100% even when doing the 720p test

SScruffy Ah. Adding the performance overlay I can now see my GPU sitting at 100% even whe...

HikariKnight•1/6/25, 11:41 AM

huh what is the gpu?

HikariKnight•1/6/25, 11:41 AM

nvm you said

HikariKnight•1/6/25, 11:43 AM

if its gpu bottlenecked then its wrong for the stats to put that in network jitter :clueless:

ScruffyOP•1/6/25, 12:08 PM

My guess is back pressure from rendering not keeping up leading to network packets not being consumed quick enough. Very curious on why this issue only surface on Linux and not on Windows, but that might be a question for the Moonlight folks. Also strange that decoding is keeping up but not rendering.

ScruffyOP•1/6/25, 12:08 PM

Gonna go check GPU usage when steaming under Windows now.

HikariKnight•1/6/25, 12:24 PM

probably a good idea

HikariKnight•1/6/25, 12:24 PM

also keep in mind that windows and linux dont use the same driver

HikariKnight•1/6/25, 12:25 PM

so could even come down to some difference in the gpu driver stack causing this behavior

HikariKnight•1/6/25, 12:26 PM

or even a regression

ScruffyOP•1/6/25, 12:33 PM

On Windows 11 GPU sits at 60-65% usage when testing 4k@120hz@150mbps

ScruffyOP•1/6/25, 12:34 PM

Same scenario but under bazzite, rapidly fluctuating between 60-100% usage, mostly on the upper end. Wish I had a graph.

ScruffyOP•1/6/25, 12:39 PM

Dropping from 150mbps to 20mbps changes nothing, which makes sense as decoding is keeping up while rendering isn’t.

ScruffyOP•1/6/25, 12:42 PM

Definitely feels like something is off when this GPU isn't able to render a decoded 4k@120hz video stream.

ScruffyOP•1/6/25, 1:49 PM

For good measure I did a rebase on stable-40, same results

HikariKnight•1/6/25, 2:03 PM

maybe check

cat $(find /sys/class/hwmon/*/ -name "power1_cap")
cat $(find /sys/class/hwmon/*/ -name "power1_cap_default")

cat $(find /sys/class/hwmon/*/ -name "power1_cap")
cat $(find /sys/class/hwmon/*/ -name "power1_cap_default")

see if those 2 numbers are matching

HikariKnight•1/6/25, 2:03 PM

essentially thats the tdp of the gpu (if its exposed) and the default tdp

HikariKnight•1/6/25, 2:03 PM

and they should be identical

HikariKnight•1/6/25, 2:04 PM

but we have had situations in the past where steam has found a way to set it to 30W which we have mitigated :clueless:

ScruffyOP•1/6/25, 4:50 PM

Nothing with the name ”cap” inside the /sys/class/hwmon tree I’m afraid

HikariKnight•1/6/25, 6:54 PM

ok then idk

ScruffyOP•1/6/25, 7:47 PM

But I believe power draw is a good lead you gave me! Looking at the performance overlay the GPU never reports more than 10w, but it’s rated for 15-45w if I’m reading the specs right. Going to try and tweak that later somehow.

SScruffy But I believe power draw is a good lead you gave me! Looking at the performance ...

HikariKnight•1/6/25, 8:28 PM

if you can find out the path that controls the tdp for that card then hand me it and i will see if i can add it to our tdpfix, hopefully it will help

Seekuhnetz•2/23/25, 11:31 PM

@Scruffy i want to get a good moonlight client for 4k @ 120 hz and with HDR in my living room. It will be its only use case.
So you got the TRIGKEY R7 6600H/660M/16GB/500GB.

Is the experience good with low latency? In your screenshot i can see an average processing latency of 7ms. Is that the correct decoding latency and does it feel smooth?
I found the mini pc on Amazon but according to the stats there it only has HDMI 2.0 which is not enough for 4k @ 120 hz. Is the information there outdated? Or are there more versions of it?
Could you fix your issue with bazzite?
Would you recommend me to buy this mini pc too?

ScruffyOP•2/24/25, 6:48 AM

I sent it back. I was having big audio dropout issues with it over HDMI. 120hz works given the right DP -> HDMI2.1 or USB4 -> HDMI2.1 adapter, but I couldn’t get 120hz moonlight streaming to work reliably on Linux, only on Windows. Considering buying a more powerful mini pc with HDMI2.1 and running Windows to achieve the 4k 120hz VRR dream.

SScruffy I sent it back. I was having big audio dropout issues with it over HDMI. 120hz w...

Seekuhnetz•2/26/25, 1:48 AM

Thank you for your answer.
Yea i feel you.
I think i will buy the Minisforum UM760.
I did a lot of research. Probably 6 hours or more and i think this is the best mini pc you can get for moonlight.
It has low latency, low energy consumption, good cooling and costs around 350$.

feedthejim•5/6/25, 10:22 PM

@Scruffy did you ever get to the bottom of the Linux moonlight issue?

ScruffyOP•5/7/25, 5:03 AM

Nah. I bought a more powerful mini-pc which is connected to the TV over HDMI 2.1. There’s no support for HDMI 2.1 in any FOSS drivers, so to be able to use VRR I have to stick with Windows

LimitX•7/12/25, 3:54 PM

Was about to say HDMI 2.1 is not supported on AMD Hardware under Linux because the HDMI Forum denied AMD the request for implementing it in their open source driver (correct me if I'm wrong here). See https://arstechnica.com/gadgets/2024/02/hdmi-forum-to-amd-no-you-cant-make-an-open-source-hdmi-2-1-driver/

Ars Technica

HDMI Forum to AMD: No, you can’t make an open source HDMI 2.1 driver

Linux users can’t hit the same resolutions and speeds as Windows—or DisplayPort.

LimitX•7/12/25, 3:56 PM

I'm currently also evaluating a HTPC for a future proof gaming (moonlight) client and probably jellyfin (fuck chromecast) and I think the Minisforum UM760 running Win (hopefully bazzite in the future when this HDMI sorted out) is a very good option

Getting Moonlight streaming to work at 120hz using a Bazzite client

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