I'm experiencing a specific issue where when using any of the MacOS 26 Tahoe betas with Low Power Mode enabled and using Vsync in fullscreen, my application framerate gets limited to a hard 30 fps. I have not experienced this on any older OS. For example Low Power Mode on 13.6 Ventura with Vsync fullscreen lets my application run at full 60 fps without issues.
Is this a bug or a change in behavior of Low Power Mode on Tahoe?
My application is 3D, runs at 60 fps and is sensitive to tearing, so I need Vsync and it is mostly utilized in fullscreen. And Low Power Mode is a default for many Macs, so default experience on Tahoe currently is a halved 30 fps. However there also seems to be inconsistencies of on which machines this happens, but older OSes are always fine.
Hello,
Given that this is beta please start with a bug report. Include GPU and Instruments traces (Metal System Trace) which can be added as attachments.
Please also mention the Mac and display hardware.
The change in behavior could be intentional for power savings.
Otherwise, take a look at Achieving smooth frame rates with a Metal display link to consider improvements for your render timing.
Optimize for variable refresh rate displays is also helpful.
