Java threading optimization at 100% CPU usage

Question

I have an application that accepts work on a queue and then spins that work off to be completed on independent threads. The number of threads is not massive, say up to 100, but

Answer 1

'Would getting smarter and managing the work load to keep the CPU below 100% get me further faster?'

Probably not.

As others have posted, 100 threads is too many for a threadpool if most of the tasks are CPU-intensive. It won't make much difference to performance on typical systems - with that much overload it will be bad with 4 threads and bad with 400.

How did you decide on 100 threads? Why not 16, say?

'The number of threads is not massive, say up to 100' - does it vary? Just create 16 at startup and stop managing them - just pass the queue to them and forget about them.

Horrible thought - you aren't creating a new thread for each task, are you?