Fan Speeds seem to vary?

[JustStarting]

I've got an Antec SX1030 case w/ the 300W PSU. The following setup below is in it, and was wondering if I am reaching the limits of this PSU. My fan speeds seem to drop a little- (by the sound of them), when surfing around. I am particularly concerned since I am adding a Yamaha 16X10X40 CDRW that I just got from Buy.com. This case has 5 drives now, and my CDRW will be the 6th- (including floppy). I also have three 80mm case fans, 1 bay fan, and a whopping 25mm YSTech fan on my Taisol. Am I reaching the limits of this PSU?

 

[jhalada]

That's by design. The fan speed is supposed to respond to load and how hot the air inside the case is.