Hello everyone, the front intake fan on my Fractal Design Define R3 Black Pearl case has been making annoying noises for years now, but recently I've been unable to quiet it down for more than a few hours at a time (by blowing with my mouth directly onto it, oddly enough). When it's making noise, its speed (measured in CPUID Hardware Monitor) drops from 1260 rpm (speed when quiet) to 750-800 rpm (making loud wobbly noises). The noises usually start when I'm ventilating my room by opening all windows for a few minutes, and the room temperature drops a degree or two. Maybe that triggers the fan to drop to half rpm? In any case, I'm sick of it and I want to replace it.

From what I gathered, I need a 3-pin fan (can a 4-pin case fan be used as well?). Will any 120mm fan do, even if it operates at 1200 rpm instead of the 1350 rpm that this defective fractal fan is supposed to operate at? Note that the front fan never reaches 1350 rpm; this speed is only achieved by the rear outtake fan, which hasn't been causing problems so far. Since this is an old PC and likely to be replaced within a year, I'm not looking to go overboard with expensive fans. I'm also having trouble finding 3-pin fans, since most of the case fans I can find in our online stores are 4-pin. I'm also not finding any fans that have the same top speed rpm as my current back outtake fan. Is using two different rpms a problem?

My motherboard is Gigabyte GA-Z68X-UD3H-B3. The current fans (front and back) are a pair of Fractal FD FAN-120.

Some candidates that I can find on the first page of Google search: BitFenix Spectre PRO 120mm (can the stupid white LED be turned off?)

Be quiet! Pure Wings 2 ventilator, 120 mm (is 1500 rpm much louder?)

Fractal Design Silent Series R3 120 mm on Amazon (though this one supposedly operates at 1200rpm)