#13891 macOS: GPU clock and power gradually ramp to maximum while OBS window is visible, immediately drops when minimized

Operating System Info

macOS 26

Other OS

No response

OBS Studio Version

32.2.2

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/hUVOtZNOzsPjBWrM

OBS Studio Crash Log URL

No response

Expected Behavior

Operating System Info

macOS 26.6.2 (25G83)

OBS Studio Version

OBS Studio 32.2.2 Apple Silicon native (Rosetta: false)

Hardware

MacBook Pro Apple M3 Pro 36 GB unified memory

External display:

4K ThunderBird R27U61
macOS scaling: "Looks like 3008 × 1692"
framebuffer reported by macOS: 6016 × 3384
60 Hz

Built-in display:

3456 × 2234

OBS configuration

Renderer: Metal
Base canvas: 1920 × 1080
Output: 1920 × 1080
FPS: 30
Color format: NV12
Color space: Rec.709
Color range: Partial
Scaling filter: Bicubic
Apple VT H.264 hardware encoder
macOS Screen Capture sources using ScreenCaptureKit
Preview is normally disabled

The scene collection contains nested scenes, cameras, macOS display capture sources, and a local browser source.

However, disabling scene items and disabling the browser source did not resolve the high-GPU state.

Problem Description

OBS can initially run at relatively low GPU power, but while the OBS main window remains visible, GPU frequency and power gradually increase.

Eventually the Apple GPU can become almost completely resident at its maximum 1380 MHz clock.

Minimizing the OBS window immediately drops GPU frequency and power back to a low state.

Restoring the OBS window causes GPU power/frequency to begin increasing again.

Simply making the OBS window smaller does not resolve the problem.

This happens even with the OBS preview disabled.

Measurements

Measurements were taken using:

sudo powermetrics --samplers cpu_power,gpu_power -i 1000 -n 5

OBS completely closed

GPU Power: ~0.25–0.42 W

GPU clock: Mostly 338 MHz

OBS running and minimized

GPU Power: ~2.1–2.4 W

GPU HW active residency: ~90%

GPU clock: Almost entirely 338 MHz

Example:

GPU Power: 2319 mW GPU HW active residency: 90.32% 338 MHz: 90% 1380 MHz: 0%

OBS visible — initial / lower-load state

GPU Power: ~3–5 W

GPU clocks: Mostly 338 / 618 / 796 MHz

Example:

GPU Power: 3538 mW GPU HW active residency: 96.58% 338 MHz: 70% 618 MHz: 27% 1380 MHz: 0%

After some time:

GPU Power: 6231 mW GPU HW active residency: 99.09% 618 MHz: 18% 796 MHz: 73% 924 MHz: 7.6% 1380 MHz: 0%

OBS visible — abnormal state after remaining open

GPU frequency can suddenly ramp to maximum:

GPU Power: 9439 mW GPU HW active residency: 75.87% 1380 MHz: 75%

Then:

GPU Power: 12170 mW GPU HW active residency: 89.44% 1380 MHz: 89%

And eventually:

GPU Power: 14288 mW GPU HW active residency: 97.73% 1380 MHz: 98%

Immediately after minimizing OBS:

GPU Power: 2319 mW GPU HW active residency: 90.32% 338 MHz: 90% 1380 MHz: 0%

This transition is very obvious and repeatable.

Important observation

GPU "active residency" alone is not the issue.

OBS minimized can still report ~90% GPU active residency, but at 338 MHz and ~2.2 W.

The abnormal state is characterized specifically by the GPU switching to sustained 1380 MHz operation and ~9–14 W GPU power.

Display capture testing

The external display capture normally adds some GPU load, but it does not appear sufficient to explain the abnormal state.

When the macOS Screen Capture target is reset/recreated, normal active display capture typically results in approximately:

~3–5 W GPU power

with clocks mainly around 338–796 MHz.

Therefore, capturing the high-resolution external display itself does not consistently require 10–14 W.

I have also observed a separate ScreenCaptureKit-related symptom where a display capture remained frozen on the macOS lock-screen frame after the physical display had already unlocked.

Resetting the display capture target can restore capture.

I am not sure whether this ScreenCaptureKit freeze and the main-window GPU issue are related.

Tests performed

Disabled OBS preview: issue can still occur
Disabled local Browser Source: no meaningful change
Disabled scene item visibility: did not resolve the high-GPU state
Reduced OBS window size: did not resolve it
Tested OBS on different displays: no consistent fix
Recreated macOS display capture: can restore capture state, but does not explain the visible-window behavior
Minimized OBS main window: consistently and immediately reduces GPU power/frequency
Quit OBS completely: GPU returns to ~0.25–0.4 W

Expected Behavior

Keeping the OBS main window visible with preview disabled should not cause GPU frequency to gradually ramp from low clocks to sustained maximum 1380 MHz operation.

Minimizing the application window should also not cause such an extreme difference in GPU power if the actual scene rendering/capture workload has not changed.

Actual Behavior

With OBS visible:

~3–5 W initially → ~5–6 W → ~9–14 W → up to ~98% residency at 1380 MHz

With OBS minimized:

~2–3 W → mostly 338 MHz

Streaming/recording/capture workloads otherwise remain active.

Additional Notes

Activity Monitor during the high-GPU state also shows significant activity from both OBS and WindowServer.

Thermal checks using:

pmset -g therm

have repeatedly reported:

No thermal warning level has been recorded No performance warning level has been recorded

The machine can nevertheless become noticeably hot during the sustained 10–14 W GPU state.

This appears potentially related to OBS main-window rendering / Qt / Metal / WindowServer interaction on macOS rather than simply scene rendering load.

I can provide OBS logs, the scene collection, additional powermetrics samples, or perform specific diagnostic tests if useful.

Current Behavior

现在只能最小化使用

Steps to Reproduce

Launch OBS Studio 32.2.2 on macOS 26.6.2 on an Apple Silicon Mac.
Use the Metal renderer with a normal 1920×1080, 30 FPS scene collection.
Keep the OBS main window visible. The Preview can remain disabled.
Leave OBS open for several minutes while the scene remains active.
Monitor GPU power and clock frequency with:

sudo powermetrics --samplers cpu_power,gpu_power -i 1000 -n 5
Observe that GPU power gradually increases while the OBS window remains visible. In my case it can progress from roughly 3–5 W to 9–14 W, with the GPU eventually spending 75–98% of its active time at the maximum 1380 MHz clock.
Minimize the OBS main window without stopping OBS, recording, streaming, or changing the active scene.
Observe that GPU power immediately drops to roughly 2–3 W and the GPU returns almost entirely to 338 MHz.
Restore the OBS window.
After remaining visible again, GPU power and frequency begin increasing again.

Additional observations:

Making the OBS window smaller does not resolve the issue.
Moving the OBS window between the built-in display and the external display does not consistently resolve it.
Disabling the Preview does not prevent it.
Disabling scene item visibility or the local Browser Source does not resolve it.
Quitting OBS completely reduces GPU power to approximately 0.25–0.4 W.

Anything else we should know?

如果我最小化使用，资源占用正常，如果我没有最小化，几乎吃满我m3pro的整个GPU