What happened?

When using Iris on macOS, using a MacBook Pro M4 Pro, when trying to play at above a 60 fps limit, the game becomes a stutter mess. It does not happen at 60FPS. Even if the fps is displayed to be consistent in game, it can be felt very easily. The only work around I've found is to set the CPU render-ahead limit to 0. This has been happening for some time. I've used Sliders vibrant shaders to test this out, and it is possible it only happens using Sildur's. I don't really know where to put this, but it's driven me crazy and might be a useful fix.

Screenshots

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Log output

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Minecraft Version

1.21.4

Iris Version

1.8.4

Operating System

macOS 15.3.1

What is your GPU?

M4 Pro

Additional context

No response