Noctua NF-A15 PWM, Premium Quiet Fan, 4-Pin (140mm, Brown)

If you don't want to read everything I have to say about this fan, let me sum it up: This fan is awesome. Very quiet and powerful. It comes with useful adapters and mounting solutions. I recommend it completely.I picked this fan up to replace the top mounted 200mm fan in my Corsair Obsidian Series Black 650D Mid Tower Computer Case (CC650DW-1) as it's a bit louder than expected and the front 200mm fan is broken (Corsair doesn't seem to care enough to return my emails about my RMA, but that's another story), so I moved the top 200mm fan to the front and removed the broken fan, leaving this one up top. Now, the 650D is designed to take dual 140mm fans as far as I know, but due to the wider design (140mm x 150mm) that isn't possible and I'm limited to just one. To be honest, I don't think I need a second fan. This one moves so much air with so little noise (currently using the low voltage adapter - more on that in a second). I'll probably get a 120mm Noctua fan to replace the stock rear fan Corsair ships since these are so great.This fan is designed for high resistance applications such as CPU fan coolers, however, it works just fine so far as a case fan. It comes with a great set of accessories including extension, split and low voltage (speed/noise reducing). Regular screws are included, as are silicone "screws" which are better at reducing case vibrations.Did I mention a 6 year warranty? On any computer part with moving components that's amazing. Fan failures are pretty common (they break down and make a ton of noise usually) so having a long warranty on this is great.

No complaints about the functionality, only criticism is the color scheme.

I have a Corsair H50 CPU cooler that uses a 120mm fan mount. Works great, but the stock fan was making a noticeable squealing noise that was driving me nuts.Now, it's important to note that, in general, the larger the fan, the lower RPM it needs to move the same amount of air. The lower the RPM, typically, the quieter the fan. This is why we're starting to see enthusiast enclosures with massive 230mm side and top fans, and this trend prompted me to look into replacing the H50 with a larger, 140mm mount radiator. But that meant ripping out the old cooler, removing and reapplying thermal paste, yadda yadda, let alone $70-80 spent primarily for an improvement in acoustics.So here we are with a high-quality 140mm fan that specializes in great acoustics AND mounts with 120mm holes. And it's on sale?! Money has not flown out of my wallet this fast since I preordered Dark Souls.Needless to say, I have this thing full-timing its maximum RPM and it is nearly inaudible. If there is any background noise - HVAC, fridge is running, or (duh) the speakers on because you're gaming - my rig is now indistinguishably silent. If I lower the RPM on all of the other fans and ensure total silence in the rest of the apartment, I can hear a noticeable buzzing/humming sound from the Noctua, but it's still preferable to the hi-pitched squealing that it replaced. ***EDIT*** The buzzing is the pump on the Corsair H50. This fan is literally silent.Performance is effectively the same, if not a little better than the stock fan. Using an i7-2600k overclocked to 4.6 GHz, the CPU rarely jumps above 49-50°C on a full load while I'm toasting away in my 80°F (~26.6°C) apartment. I would be shocked to see it break 45°C on a cooler day and chances are I'll lower the RPM during winter, simply on principle.If, by chance, you are in the same situation that I'm in - don't bother buying a new heatsink/cooler and just grab one of these. Better yet, grab two and let us know if a push-pull configuration is worth it!

I ordered this along with a NF-F14 PWM to replace the stock non-PWM fans on my NH-D14 CPU cooler. After installing these fans, I noticed a "clicking" noise common with PWM fans. After reading reviews and descriptions from Noctua's website, I was led to believe that Noctua had eliminated the dreaded clicking associated with PWM fans. I was ready to send these back and go back to the stock fans when I decided to make sure these were the culprits. After process of elimination, I determined it actually wasn't these fans, but one of the stock fans on my case! I hadn't noticed it before due to the stock NH-D14 fans being a little louder, but these are so quiet it allowed me to hear the subtle clicking from the stock Corsair AF140L on my case!Do not doubt Noctua, these are the real deal. At idle speeds, these are seriously about as close to silent as you can get. During gaming or other CPU-heavy applications, these will ramp up, but are still extremely quiet compared to other fans. Although they run at slower RPMs at idle compared to the stock fans on the NH-D14, idle temps are about the same, and load temps are equally low as well. I'd give them six stars if the color scheme wasn't so butt-ugly, but they're actually kind of growing on me...Note: If you're getting this to replace the stock 140mm fan on a D14 like I did, you'll have to position it so that the longer axis is perpendicular to your motherboard. The metal wires from the stock 140mm fan on the D14 that attach the fan to the heatsink will not fit over the extended "anti-vibration" pads (even if you take the rubber pads off). You might be able to modify the wires to work, but I didn't want to break them. Even with the way I positioned it, I had to use a little force to get the wires to fit, but I eventually got it and it's working perfectly.