It's misleading. Since you are running hyperthreading, your computer is busy, but the maximum of all tasks together will be reported as "50%".

If you are running another heavy task in addition, you may consider turning hyperthreading OFF to eliminate a lot of thrashing to use the Floating Point Unit. There's only one, and the grid program makes extensive use of it.

If you are mainly crunching, it should not make much difference.

Please look here. You mentioned 40% instead of close to 50%. There may be something in there using a good deal of CPU that you may not know about. I would look for that other 10% and see if I could find out what is using it. ... A computer that is not doing anything but running the WCG should be reporting near 50% on the WCG.

Regards.

Your readings will have changed now that you have turned off the HT. Your total throughput will remain very nearly the same. Kind Regards.

Remember, it was pegged before, it's just that Windows doesn't know how to accurately represent the CPU utilization with HT turned on.

HT may increase or decrease the throughput of Rosetta, but any affect that HT has will be so minimal as to be negligable. The reason for this is because it runs at the lowest priority and thus everything else gets first shot at the CPU.

As for other programs, it depends. Sometimes HT increases throughput, sometimes it reduces it. You just have to benchmark with what you normally use and find out for yourself.