Console app usage throttled down while system is idle

I have a number-crunching console application that will
take a while to run (days). I am seeing that the process
initially takes all of the CPU it can get (near 100%).
After a couple of days of this, the process uses about 30%
of the CPU while System Idle Process gets the remaining
70%. I would like the console app to continue to gobble
of the CPU it can get all of the time. The process is
running on a machine dedicated for this purpose, so it not
a matter of competing resources.

Any ideas on what I can do to keep the console app
charging along with as much CPU as possible?

Thanks,
Geoff