Increased fps drops cpu usuage?

[zammbi]

I found that changing my fps from 24fps to 30fps dropped my cpu usage about 66% I tested this in 2 games.
I thought this was very weird.
Of course if I increase the fps more it will increases the cpu.
I'm just doing basic active rendering using BufferStrategy.
I have a few ideas why, but would like to hear out an official answer.

[trembovetski]

is the game full screen or windowed?

Dmitri

[zammbi]

Windowed. Though haven't tried full screen.
I guess this answer doesn't really matter, just thought it could help people if they think having low fps keeps the cpu low.