Summary: After installing 2 of these in a Coolermaster Cosmos S, I ended up with a total of 4 FN121's the other two being the lesser powered LED versions of this fan. This fan is very quiet, my system is however reasonably loud due to my Video card and CPU heatsink fan AND the fact that my case is aluminium and has TONS of ventilation spaces. These are factors you have to take into consideration if you are aiming for a quiet PC. 1.
Summary: For those of you that want a little more than the vague description, the technical specs are: Size: 120 x 120 x 25mm Power: 4 Pin Molex Noise: 26.6 dBA Airflow: 53.24 CFM Speed: 1200±250 RPM Sleeve Bearing I purchased two of these to upgrade the stock fans in my Antec 900 and noticed a lower ambient temperature by 2-3 degrees (celcius) Noise is ok. Not loud, but noticeable. Can easily be remidied with a fan controller.
Summary: Ok, so this is a large case fan (most people are probably looking for an 88mm instead of a 120mm case fan). And not having the computer or replacement in front of me I bought the wrong fan. Not the product's fault or Amazon's... My fault....... I actually used it anyway because it did fit the case and securing it wasn't a problem. But then I have been known to do a lot of (sometimes crazy) stuff to keep computers cool.
Summary: I got this to add to my MANY collection of fans in my rig. Its doesn't look at nice as my Rocket Fish or Cooler Master but no one will see it. I think of it as my red headed step child. I think I paid like $4 bucks for it but if know someone who works at BEST BUY, they get wonderful discounts on non-national brands. I got (5) 120mm Rocket Fish fans for $3 bucks a piece.
Summary: thought this was a 12mm case fan because of my cpu cooler theres not enough room for a normal sized fan and saw a couple reviews mentioning how small this fan was. well its 120mm x 120mm x 25mm. why is it 8in x 8in x 2in in the amazon description?
Summary: I bought this to replace a Xigmatek fan that had red LED's (which I didn't like the look of in my new case). This fan made my PC noticiably louder. I may just cut the LED wires on the Xigmatek and go back to that one. Guess I should have compared the noise specs between the two before purchasing this fan. A $6.99 lesson in the value of careful forethought...
Summary: This is a great fan but it does not vary RPMs very much. It's always around 1390 or so. It plugs into the 4 pin molex for power and has a 3 pin with one wire to plug into your motherboard but it the motherboard can't change it's RPM. It just reads it. It is a good fan though. It moves a ton of air and is very quiet. I think it's the best fan I have. I just wish it was controllable.
Summary: I bought this fan to replace the degrading fan in my PSU which was making horrible sounds after 2 years of ownership. I found out it was the fan so I promptly found the dimensions and ordered this fan. Took apart and installed the fan. Works as intended and the PSU temperature is a little cooler. No sound issues as well. I had to splice some wires, but thats just part of my transplant. I would recommend this brand and fan to others. The holes fit perfectly too.