The system will use as much of the processor as it can.
In recent releases, it will use all available processors.
There may be ways to speed up your generation, but we need some more information...
How many cores do you have?
What release are you running?
What kind of operation?
Also, the CPU display in task manager can be confusing. For example, if you run a 4 core processor in an old release, the CPU will max out at 25% - all of one processor. If you generate the same path now, you will see 100% because multi-threading uses all 4.