I downloaded and installed the latest experimental version of BOINC (5.8). While looking at CPU usage in WinXP"s Task Manager, I observed the CPU usage bouncing up and down like a yo-yo. While set at 50%, it would bounce from 30 to 80% like clockwork. is this normal for this feature? Will later builds attempt to even this out some?

The BOINC throttling feature works in 1 second intravals. So you will see this bouncing if you use this feature. I don't think that it will be changed, finer control requires more processing time to be spent doing the throttling.

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BOINC WIKI

BOINCing since 2002/12/8

If you want to know all the time-out options it uses, there is a table in this FAQ. :-)

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This argument of a throttle control eating CPU time is a bit feeble. As a long standing user of Threadmaster, it just registers few seconds a day in the taskmanager! It's granular control is very fine and on my box is in charge of allocating CPU time for multiple processes. No yo-yo effects whatsoever.

The CPU time taken will depend on the method used to suspend and restart each process. If (for example) it's using the standard Boinc suspend and resume, which uses an API between Boinc and the Science app, then you should expect a significant overhead.

Remember that Boinc is multi-platform, and has to avoid using techniques which are platform dependant. It is likely that ThreadMaster uses Windows API calls which don't have a direct equivalent on the other platforms.

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Adding to Mike's comment;

Most Windows based CPU throttling options use the Windows registry.
BOINC is multi platform, while only Windows has a registry. So BOINC needs to find a different way to throttle the CPU if it's used on all platforms.

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