Renoise had poor graphical performance on macOS ever since I switched to Retina macbook a few years ago.
When I was on 10.14 Mojave, setting a tick to run app in ‘low resolution mode’ helped without making app blurry (it looked pixel perfect). However, it looks like filtering algo was adjusted for Big Sur, and Renoise is now unusably blurry in low res mode.
Luckily, I found a solution that makes Renoise perform well without low res mode, and even with HiDPI support on – you just have to switch display profile from ‘Color LCD’ to ‘sRGB IEC61966-2.1’, that’s it!
If you have several profiles called ‘sRGB IEC61966-2.1’, choose one that shows ‘/System/Library/ColorSync/Profiles/sRGB Profile.icc’ path when hovered.
Tested with Renoise 3.3.2