I just wanted to say that process/thread with lower priority
will always give CPU cycles to process/thread with higher if
that higher process/thread will really need that CPU time...
If you want to reduce the power bill you should stop Bitcoin
generation. Each generated bitсoin is confirmation of costs.
You can change the source code that it uses less CPU time,
but I don't think that you can generate with a low khash/s.
Bitcoin uses Normal process priority (15..1) and Lowest thread
priority (22..2) for bitcoin generation thread. It is priority level
6 so bitcoin generation thread will always gives CPU cycles to
other processes/threads if they need it because they usually
have priority level higher than 6. Most have priority level ~8.
If you'll change Bitcoin's process priority to Idle (15..1) withTask Manager
or Process Explorer
then bitcoin generation
thread will have priority 2 and will give CPU cycles to every
process/thread with priority higher than 2 (read: to every).
Usually this is not necessary. Default setting is the best.