I am running eight different projects including PrimeGrid which is the subject of my questions. Originally I had set the "Max number of threads for each task" preference for my PrimeGrid account to 2. New PrimeGrid tasks were showing up in the Task list for the BOINC manager with the annotation (2 CPUs). I changed the preference to 4 to see if I could get increased performance on the multi-threading tasks. Occasionally new tasks would take advantage of this update and show (4 CPUs) when they were running. I have since changed the preference back to 2, but am still seeing new tasks that use 4 CPUs. I have updated the PrimeGrid project in the BOINC manager after each change.

There is no entry for ncpus in the cc_config.xml file. The PrimeGrid folder in the BOINC data directory does not have an app.config file. All I find is a init_data.xml file in the Slots directory for the task reporting 4 CPUs which has the max_cpus set to 2 and the ncpus set to 4.0.

How do these two settings interact with each other and how do I get the PrimeGrid tasks to use a maximum of 2 CPUs?

BOING Version 8.2.4 (not installed as a service)
Windows 11 25H2

I have since changed the preference back to 2, but am still seeing new tasks that use 4 CPUs.

Is this tasks that downloaded after the change back to 2, or "new" tasks that were already downloaded but hadn't started yet?

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https://boinc.berkeley.edu/dl/

There is a bug in 8.2.4 Boinc client.

I did report this problem September. No answers.

Only solution to use PrimeGrid's "Max number of threads for each task" is to use older 8.0.2 Boinc client. https://boinc.berkeley.edu/dl/?C=M;O=D

In reply to WezH's message of 25 Nov 2025:

There is a bug in 8.2.4 Boinc client.

I did report this problem September. No answers.

Only solution to use PrimeGrid's "Max number of threads for each task" is to use older 8.0.2 Boinc client. https://boinc.berkeley.edu/dl/?C=M;O=D

Have you ever reported this to GitHub?

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BOINC maintainer.
For any insight, check my BOINC Development Blog.

These are tasks that were downloaded after the change back to 2.