Hauptwerk Virtual Pipe Organ

I added Reaper using VST link to get the compressor function. It appears to be working correctly, and other than changing the audio output from my device to the VST link made no other changes to Hauptwerk audio. Now the CPU meter is going crazy, constantly moving in red. I'm not hearing any audio glitches when this happens. When I check the CPU usage in the Task Manager, that seems to be fine.

Any thoughts?

You should check Reaper's and Hauptwerk's core affinities and priority. If it is bound to the first two physical cores, Reaper may be interfering with the audio driver and some HW time-critical threads. HW needs to be at Realtime priority, and you may need to untick the Advanced General preference "Bind audio engine threads..." to see if that helps. If Reaper lets you reassign its core affinities, make sure it and HW are using different cores where possible, or set them both unbound and see if Windows can schedule the work better.

Also in Task Manager, try View Logical Cores. If any core is running close to 100%, you may have too much (app and driver) work bound to that core.

Hello David,

To add to Mark's reply, provided that Reaper is using an ASIO (Windows) or macOS audio driver, and if Reaper's driver buffer size is set to a power of two (e.g. 512), then also try setting Hauptwerk's audio buffer size to the same value and setting its number of buffers to 1.

Thank you both Mark and Martin. I changed HW to Realtime priority, which immediately helped. I also changed Reaper cores removing the first two and changed the audio buffer size to 512 and number of buffers to 1. CPU meter is now staying in the green.

Thanks, David. Excellent.