I have boinc running at 100% on all 8 processors. When I do this I notice that my turbo boost no longer turns on. If I lowers boinc to about 75% I notice that the turbo boost turns on when the core usage is less than 100%

Can anybody explain this? Can I keep the turbo boost on even when at 100% usage

Whether the processor Turbo Boosts depends on how much power it pulls, it's cooling etc,

My i5-3210M will Turbo Boost to 3.1GHz when running a single thread, but will only go to 2.9GHz when running multiple threads,
If things are too hot it'll drop the clock in .1GHz steps,

So make sure your cooling is up to scratch.

Claggy

Maybe it is cooling but it seems to happen instantly as soon as I se the process to use 100%. It seems like it would take a minute for it to get hot.

Dave

It sounds like it is working exactly the way Intel designed it. It's not just the current temperature which is taken into account, but workload and power consumption as well. Wikipedia has a quite accessible article, with examples.

Intel Turbo Boost

Thanks for the great link. I think you nailed it on the head; considering the workload and the pending workload I can see why turbo boost would turn on and off.

Now for the big question: should I reduce the %CPU time to 50% and have the processor process faster at near 2+ Ghz (probably averaging 1.8GHz) or should I use 100% and only process at 1.6Ghz. If I use even less %CPU it will probably boost even faster. How can one determine the best balance. Which is more productive, %CPU time or cpu processor speed?

I suppose experimentation would be the best way to determine that. Any suggestions?

Thanks,

Dave