macOS 26 decoding latency is too slow

[zhaoxuan]

I recently upgraded to the latest macOS 26.0 Tahoe, Moonlight decoding latency increate to 80ms.

Client PC details (please complete the following information)

• OS: [mac OS 26]
• Moonlight Version: [v6.1.0]
• GPU: [Intel Iris Plus]

Server PC details (please complete the following information)

• OS: [Windows 10 latest]
• Sunshine or GeForce Experience version: [Sunshine v2025.829.135256]
• GPU: [RTX 2060]
• GPU driver: [latest]

Moonlight Logs (please attach)
Moonlight-1758166237.log

[sandramaria11595-max]

Xhxdhvdd4y

[AlexisEvo]

Yeah this is absolutely atrocious after upgrading to macOS 26, my video decoding latency is spiking to >100ms. It seems to primarily happen when in windowed mode. In fullscreen it's still pretty bad, around 20-25ms, but much lower than windowed. Tried vsync/frame pacing both on and off.

OS: macOS 26.0 25A354
Moonlight version: 6.1.0
GPU: Intel UHD 630 / Radeon Pro 5500M

Macbook Pro 2019 16", the last Intel model

[cgutman]

It looks like both of you have older Intel Macs. Is anyone experiencing this with Apple Silicon Macs?

Can you try to run Moonlight with the Metal renderer disabled? You can do so by running it from Terminal with the following command:

VT_FORCE_METAL=0 /Applications/Moonlight.app/Contents/MacOS/Moonlight

[throughhim413]

Can confirm I was experiencing the same issue on Apple Silicon - 2024 Mac Mini M4 Pro.

Running with the Metal renderer disabled resolved my latency issues and it's running like it was before.

Edit: If it's useful, log stats from metal enabled vs disabled:

Enabled

Incoming frame rate from network: 36.98 FPS
Decoding frame rate: 36.98 FPS
Rendering frame rate: 20.97 FPS
Host processing latency min/max/average: 3.8/230.0/4.5 ms
Frames dropped by your network connection: 0.00%
Frames dropped due to network jitter: 30.56%
Average network latency: 1 ms (variance: 0 ms)
Average decoding time: 2.37 ms
Average frame queue delay: 36.24 ms
Average rendering time (including monitor V-sync latency): 1.06 ms

Disabled

Incoming frame rate from network: 58.66 FPS
Decoding frame rate: 58.66 FPS
Rendering frame rate: 58.60 FPS
Host processing latency min/max/average: 3.8/230.0/6.6 ms
Frames dropped by your network connection: 0.05%
Frames dropped due to network jitter: 0.08%
Average network latency: 1 ms (variance: 0 ms)
Average decoding time: 2.69 ms
Average frame queue delay: 8.61 ms
Average rendering time (including monitor V-sync latency): 0.28 ms

The log from Metal enabled was full of SDL Warn (0): Presentation wait timed out after 100 ms

[AlexisEvo]

That slowdown doesn't appear to be from decoding time, but rather network jitter, which may be another issue we've been experiencing on macOS -- #1598 . The "Presentation wait timed out" is present there as well.

I attempted to run without the metal renderer, but am getting very inconsistent results across the board, between this new issue and the Sequoia network jitter issue. Rarely I'll get decoding time as low as 3-5ms, most of the time it is around 25-30ms, with both metal rendering and non-metal rendering. Sometimes spiking up to >120ms until I restart the stream.

The one thing that consistently lowers decoding time to <5ms is disabling hardware acceleration. With software decoding it is always fast, but obviously uses quite a bit of CPU.

[throughhim413]

Thanks for the correction. I hadn't experienced the issue before Tahoe, so I'd assumed it was the same as you'd described.

[Pointyguide]

I am getting the same performance as always, running M4 Pro, both host and client connected to gigabit ethernet. No degradations or improvements.

[yanto3000]

I experienced higher latencey (not as high as OP) after reinstalling a fresh MacOs26 on my M2 Pro, and i have clones the github rebuilding the app and enabled Game mode and i am back down to around 3.3-3.7ms at native resolution hdr on 120hz

[tranbaohuu]

Can confirm I was experiencing the same issue on Apple Silicon - 2024 Mac Mini M4 Pro.

Running with the Metal renderer disabled resolved my latency issues and it's running like it was before.

Edit: If it's useful, log stats from metal enabled vs disabled:

Enabled

Incoming frame rate from network: 36.98 FPS
Decoding frame rate: 36.98 FPS
Rendering frame rate: 20.97 FPS
Host processing latency min/max/average: 3.8/230.0/4.5 ms
Frames dropped by your network connection: 0.00%
Frames dropped due to network jitter: 30.56%
Average network latency: 1 ms (variance: 0 ms)
Average decoding time: 2.37 ms
Average frame queue delay: 36.24 ms
Average rendering time (including monitor V-sync latency): 1.06 ms

Disabled

Incoming frame rate from network: 58.66 FPS
Decoding frame rate: 58.66 FPS
Rendering frame rate: 58.60 FPS
Host processing latency min/max/average: 3.8/230.0/6.6 ms
Frames dropped by your network connection: 0.05%
Frames dropped due to network jitter: 0.08%
Average network latency: 1 ms (variance: 0 ms)
Average decoding time: 2.69 ms
Average frame queue delay: 8.61 ms
Average rendering time (including monitor V-sync latency): 0.28 ms

The log from Metal enabled was full of SDL Warn (0): Presentation wait timed out after 100 ms

Hi, How to disable Metal Rendering?

[tranbaohuu]

I experienced higher latencey (not as high as OP) after reinstalling a fresh MacOs26 on my M2 Pro, and i have clones the github rebuilding the app and enabled Game mode and i am back down to around 3.3-3.7ms at native resolution hdr on 120hz

could you share your .dmg with gamemode?

[yanto3000]

Use this fork

https://github.com/andygrundman/moonlight-qt/releases/tag/v6.1.0-game-mode

[tranbaohuu]

Use this fork

https://github.com/andygrundman/moonlight-qt/releases/tag/v6.1.0-game-mode

Thanks!

[DamnitKarl11]

I have the same issue, the Game Mode fork above did not help but disabling the Metal renderer did, it's back to being nice and smooth at 4k120fps on my M1 Pro.

#1696 (comment)