[SOLVED] Odd performance issue on macOS

I’ve described on VCV Rack’s GitHub issues here https://github.com/VCVRack/Rack/issues/1864 a strange issue I’m experiencing, and hope the community of non-developer perhaps can help too.

I am relatively new to VCV Rack and I am loving it, but even running relatively small projects it seems to have performance issues, despite my Mac being a relatively powerful one. See the video at https://youtu.be/EhYYE4TTOK4 for example and hear what happens to the audio when I activate the meter.

Switching application, say using Chrome to browse the internet, also disrupts the audio. The issue sometimes happens also while being in VCV Rack doing nothing in particular. My hypothesis is that the smallest other task starting by itself on the Mac disrupts VCV.

The only characteristic of my projects is that I like to integrate Rack with real hardware, so I have two audio cards connected and half a dozen CV and gates going in and out. However, even the Rack default basic project seems to suffer, so that must not be the problem.

Any idea? Does this happen just to me? I love Rack but before I invested more time in it I’d like to be sure I’m not going to hit a wall sometime soon when the issue becomes unmanageable. Thanks!

realtime thread priority setting will keep your browser from stealing cpu from rack (although it looks from the video like you set that already.). other than that, you can find literally hundreds of questions just like yours here. search for them. And read the part of them manual that talks about this issue.

But your issue is odd. when you show the CPU meters, they all look really low. Yet the bug report is titled “disproportianate CPU usage when using rack”. I don’t see it. Was one of the meters really high white you were filming the floor?

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Try increasing the buffer size set in the Audio-module.

Also, there is a known bug in v1.1.6: When using full screen mode any sort of frame-limiting is defective. Try switching to window-mode instead.

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And you are using two Audio-modules in your patch. Multiple Audio-modules are not supported in Rack v1.


Also reduce the number of threads :

I also posted on github.

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All, a quick note to thank you and share that my experimenting during the last few days took me to a place where I’m more comfortable of investing time and worth working in Rack. Keeping the sample rate consistent between Rack and the audio module, keeping the audio module buffer at 128, using one audio module only (sometimes :stuck_out_tongue_winking_eye:) and not running Rack in full screen has generally improved a lot my experience of it.

Still, I’m looking forward to version 2, also perhaps spoiled by how more performing Bitwig Studio is in comparison. It shows me what is achievable. In the meantime I’m supporting the project purchasing modules here and there. What the VCV developers and community have achieved is already amazing, I can only look forward to what comes next.