Nexus 80mm 'Real Silent' fan - what's up?

Arfa · Post by **Arfa** » Fri Feb 13, 2009 3:28 pm

Just got a Nexus Real Silent 80mm fan, its the PWM series. OK first up I thought my mobo had multiple PWM header, but no, so I'm plugging this into a normal 3 pin header. Either way its really noisey!! Not at all like I expected. It produces a good loud hum, louder than my E7200 stock fan and the fan in my Seasonic SS-300TFX PSU. Certainly not the 16 dB they claim or the 20dB the round up here reckons.
I've got a 92mm Nexus, which is much much quieter.

So have I just got a bad one? A dodgy knock off? Or is something weird going on because I plugged a PWM fan into a 3 pin header?

Post by **NeilBlanchard** » Fri Feb 13, 2009 7:24 pm

Hiya,

It seems like you may have a bad one -- especially if it is louder than the 92mm -- are they running at similar speeds?

jessekopelman · Post by **jessekopelman** » Fri Feb 13, 2009 10:53 pm

Despite sharing the "Real Silent" name, I don't think Nexus PWM fans are the same fan as the non-PWM versions. In fact, I'm sure this is the case for the 80mm, since its 2800RPM top speed is almost twice the 12V speed of the non-PWM version. Your problem is that by putting a PWM fan in a 3-pin header you are running it at full speed and 2800RPM is not going to be anything like quiet, let alone silent.

Arfa · Post by **Arfa** » Fri Feb 13, 2009 11:36 pm

Didn't take not of its speed, shall have to check that one and compare against the 92mm one.

That said I think if I drill some extra holes I should be able to fit the 92mm one my case anywhere, which will probably be a better route all round. Only thing is my cases has rounds edges, so I won't be able to mount a 92mm fan flush to side of case, it will have to be about 1cm away from case. Will this affect its efficiency and should I consider a little ducting to fill the gap between the fan and case wall?

vertigo · Post by **vertigo** » Sat Feb 14, 2009 7:58 am

Hi Arfa, before you make any mods, test it with a slower speed. Not many 80mm fans are quiet at stock speeds, it's not like with 120mm's.

samuelmorris · Post by **samuelmorris** » Thu Feb 19, 2009 3:28 am

3-pin headers don't have PWM control, so the fan will be running at full speed. At full speed The PWM Nexuses run at DOUBLE the speed of the normal 80mm ones, 2800rpm vs 1500, and any 80mm fan is noisy at that speed.