Fans flicker during activity

Hola, I just finished building my system (except for my video card and LCD) and I have a problem already. I can't win. Anyway, I'll post my specs and get on with it:

Antec TruePower 480w
DFI LANParty UT nf3 250gb
AMD Athlon 64 3000+
Corsair 1gb PC3200 Value
Maxtor 200gb 6Y200P0 IDE
Some crap Leadtek GeForce 4 card
Onboard sound till my Audigy gets here
Windows XP Home SP2 (x64 not quite obtainable yet)

The problem is that when my computer does anything simple like open a webpage or play a song, my back two case fans (and only my back two, which are the only ones connected to my mobo) flicker in sync with my processes. I've also noticed that sometimes when I fire up my system my bottom case fan will shutoff completely and come back on when Windows is finsihed loading. What's up?

[Jason425]

I'm guessing that that may be a feature of the motherboard?
That or your power supply or motherboard is having big time problems

[vee_ess]

It could be that the fans are thermal controlled, but those usually have a range of speeds for that and do not shut down. I would say that it is probably a lack of power, however, the big 3 for power are CPU, video, and HD, but you have only 1 hard drive and a weak video card to drain a 480 watt PS. Try disabling your onboard components, such as sound and integrated network card to see if that helps at all.

[Tyler]

Are the fans connected directly to the motherboard or the power supply?