I bet these fans are just plugged in then yeah, so they'll be going at there default speed. Do they also glow in that case?
If they were ones that plugged into the motherboard, this would instead control the speed and so they would spin faster, and could work with Cool n Quiet technology if you had an AMD processor.
If they are plugge using 4pin connectors, you might find you couldn't put a fan controller on them to speed them up/slow them down...well I wouldn't think you could... or maybe those are the ones where you can
I'll have to check on this