Hard Drive slow to wake up in Vista

[WiNgY17]

Hey guys, just wondering if any of you know what's going on with my new rig.

Q6600 Intel Processor
Asus P5k Dlx MB
evga 8800gts 512
4 gb DDR2 OCZ Plantinum RAM
2 x 500gb SATA Western Digital Caviar SE 16 HDDs (non raid)
Antec nine hundred case
Windows vista 32bit

It's a strange little "problem" i'm having everytime i get back to my computer after leaving it alone for about 5 minutes. The only energy saving feature i have is turning off the monitor after 5 minutes of idle time. When i get back to the computer, the screen turns back on and i can start to do whatever i want to do. Then after about 10 seconds, things kinda stop loading and i can hear the hard drive making a wind up "start up" noise as if the disc is finally loading (almost sounds like a fan going from idle to low power setting. After about 5 seconds of this, everything opens up as requested... and about 10-20seconds later, the same things happens again (stop in HDD activity.. noise.. back to normal). and then everything works fine.

It's not a huge problem because it doesnt really affect anything except my patience everytime i sit down on the computer for the first time.

Anyone know what could be causing this and how to fix it?

[-n7-]

This might be worth checking out
If you want the HDD to never spin down, set it to 0.

[WiNgY17]

N7... thanks a lot for your help. I'm pretty sure that must have been it. The hard-drive was set to stop at 20minutes. Cheers!