There doesn't seem to be any UI for managing Virtualbox from Boinc.
I find that only 8 threads are run which corresponds to 8 work units run at a time.
I have 16 cores which support up to 25 threads so Boinc is using 1/3 of my processors capabilities.

Adding cores to the VMs doesn't work for some reason.

Does anyone have a clue how I can get boinc/virtualbox to use all more cores & threads?

Thanks

There doesn't seem to be any UI for managing Virtualbox from Boinc.
I find that only 8 threads are run which corresponds to 8 work units run at a time.
I have 16 cores which support up to 25 threads so Boinc is using 1/3 of my processors capabilities.

Adding cores to the VMs doesn't work for some reason.

Does anyone have a clue how I can get boinc/virtualbox to use all more cores & threads?

Thanks

What is your hardware environment?

What software?

Which Boinc projects are you running?

As a wild guess you don’t have enough memory but …

Posting the first 50 lines of the event log after a restart would be a great help.

yeah, make sure the amount of cores assigned to the VM are 99% or lower (leave 1 cpu thread for OS operation).

Like above said, it could be either:
1- The VM is configured to run fewer cores/threads than what you actually have, and thus the software can only access those,
2- Boinc is assigned only a few cores (eg: 33% of CPU resources)
3- Not enough ram is allocated in the VM to run that many WUs, or the RAM the WUs need to run, exceeds your actual RAM.
4- Either on the project's website, or in app_config of the project, a limitation is set to the # of CPU threads per WU type.