case fan suddenly drops 1,000 rpm

I have a scythe s-flex fan I got a while back, maybe a year and a half or so. It was nowhere near being silent as it claimed, but it moves a crapload of air so I kept it. It's a 1600 rpm model, but just a couple days ago I noticed my case was a lot quieter. Stuck my hand behind the fan and could barely feel any movement, so I opened up abit EQ and sure enough the fan is only running at 600 rpm. There are no fan controls enabled. Anyone know of a reason why it might do that other than being on its way to dying? If it's gone bad, I'm never buying another scythe fan again. For $16 it BETTER not already be dead. Especially since it's also louder than the stock case fans when it claims to be "silent".

 

nevermind, it seems to have come back now. that was weird.

 

The fan is most likely heat controlled, and due to it being winter your temps probably dropped meaning the fan speed span down a bit.

Glad it's working again though!

 

I'm pretty sure it doesn't have a sensor, it's just a black hunk of plastic with a 3 pin connector. It probably was the abit EQ software interfering even though I had it set not to. It's been acting strange setting off alarms randomly when nothing is wrong and the alarms are disabled. o.0

 

The temp of the CPU is sent to the BIOS, then the BIOS can control the speed of the fan.