Sometimes members ask about the % of CPU use they see on average for a science process and observing that it does not agree with the value that was set in the device profile. For instance the Default setting in the Standard Settings profile is 60% but when looking in the task manager they only see ~30% indication. The reason is that process/task managers tend to only tell the % used from the Total available CPU time perspective and not the % per processor core [or hyper-thread as may be].

In the screenshot sample below you see how 4 science tasks are running on a quad core processor. The setting is 100% and because it's cool enough in the room, the temperature control utility (here the 3rd party TThrottle, see FAQ ), has not lowered the use. Though each science task uses ~21 to ~25 %, the sum of the 4 tasks + what other applications are using is totaling to about 100% (orange framed box at bottom).



Because the BOINC internal throttle is designed as a 'thermal control' and NOT as a 'smooth experience', the above mentioned TThrottle much better at this, the default of 60% CPU time after switching from 100% looks like the below screenshots.



It's obvious, going up and down at 60%, switching between 3 seconds running at 100%, each per process independently, and 2 seconds pausing as the cooling period, this is working out as a total system load of 62% in the example (total system).

The next screenshot shows the computed mean nearing 15% which multiplied by 4 tasks approches the targeted 60% load. It will never be exactly 60% simply because BOINC uses idle / spare CPU cycles, so if the system is really busy, the sciences automatically get less.