cpu 120mm fan?

[sasrob]

is there any way of useing a 120mm fan for a cpu i am trying to think of a way of doing that i'v seen the 92mm fans but not 120mm would it make for batter cooling???

[XeroHouR]

mostly quieter, but you could then run faster, louder ones to make up teh difference. You can buy 80mm to 120mm adapting vents, or an xp120 from thermalright and just mout it right up.

[danrok]

You can always make your own duct:
http://www.spodesabode.com/content/article/ductguide/3

[GrahamGarside]

There are as few 120mm compatable heatsinks, and you can always duct one to a smaller heatsink.
The biggest benefit is increased airflow, as for being quieter, yes you can get the same airflow at lower rpm, but it's much easier to get a quiet 80/92mm fan than a quiet 120mm fan, you need a 120mm fan to spin very slow to be silent, like 500-900rpm, where as an 80/92mm can afford to run about 900-1200rpm
If you're cooling a prescott or newcastle/clawhammer then it's worth going for a 120mm cooler, in fact with a prescott it's pretty much manditory. Anything less and you are probably better off with a 92mm fan for quiet purposes.
Of course for ultimate cooling regardless of noise then the 120mm coolers are best all round

[XeroHouR]

yea, thats the point i was shooting for with not so many words. Basically sound/rpm airflow/rpm and sound/airflow the 120mm is prolly the best. If you want silence alone, find Coolermasters 17dB 15CFM fan, won't do a whole lot, but its quiet lol :P

if u wanna know about noise, just think that roughly(for the range fans are in) you double the noise for every 10dB(man thats a ball park figure)

[GrahamGarside]

actually you double the noise for every 3db, most rooms ambient noise will be 25-30db and less than 20db will be effectively silent from more than a metre away and any fan making claims of less than 15db is just plain lieing.

[danrok]

Originally Posted by GrahamGarside

any fan making claims of less than 15db is just plain lieing.

Yeah, you wouldn't be able to hear what it was saying anyhow.

[sasrob]

i did buy a few of the tornado fans god it sounds like a jet taking off with 2 of them as case fans the thing is it's the epox 9npa-ultra and i think a 120mm fan would be hard to fit as the 24 pin 4 pin are close to the cpu heat seek?

[danrok]

Hard to fit using which method, 120mm heatsink or 80mm with a duct?

Ducting shouldn't be a problem.

[XeroHouR]

i put 2 tornados on a thermaltake tower 112 once. It sounded like a train going by. I couldn't imagine using 2, I ran one for a while. The temps are nice for air, but the sound wakes the dead! I saw a guy who used 5 of them on his case. Can...you....imagine.

As for ducting, you can make a duct out of anything really, even a tunnel of duct tape works, but preferably something hard to make the shape is best, or you can buy the UV reactive ones for little cash.

[sasrob]

useing a 120mm for the cpu fan !!!! and five tornados was his hearing ok!!! my set up 1x 120mm front 2x80mm back was the 2 tornados but to much sound for me

[keithwalton]

Originally Posted by GrahamGarside

any fan making claims of less than 15db is just plain lieing.

db yes there lieing, db(a) however perhaps not depending on the frequency because of the 'a' weighting curve.

See, http://www.phys.unsw.edu.au/~jw/graphics/dBA&C.GIF

As for a duct keep the rate of contraction under 10degrees (5 deg per side in 2d view) to minimise pressure difference

[GrahamGarside]

Even dba ratings below 15 are far fetched, this means you silenX!

For instance SilenX claim one of their 120mm fans is only 11dba at 1400rpm which is just fiction, even a 1000rpm fan would be hard pushed to come under 20dba

[keithwalton]

lets see 1400 rpm is approx 23.33 Hz assuming the peak sound power level is around the cyclic speed 23.33Hz gets an approx -50db on the a weighted scale! Thats a hughe drop. Although it is just on the upper fringes of the tactile frequency band. Nice! (not!) You would actually have more trouble sleeping with a quiet fan that resonates at a low frequency than a slightly louder one at a higher frequency. The 6-24Hz range is v.bad for your mental health!

Aaah for NVH and the secrets of the motor industry

Edit - Just noticed this is post 666, quite apt for the sinister nature to it. Oh how I could misuse the teachings of the NVH module i'm doing to make people ill. (NVH = Noise, Vibration & Harshness, aka Automobile 'refinement') refinement being an apt word as i'll let you into a little secret, any car manufacturer that claims there car makes you feel awake and alert etc after a long journey is because they have tweaked the interiour acoustics to resonate at a frequency that causes insomnia!

[sasrob]

do anyone have a duct going to there graphics i am thinking of just useing half of my bottom 80mm fan as a duct for my graphics card i'm not too sure how to fit it to the fan?? whats the best way then?

[noorman]

Originally Posted by sasrob

is there any way of useing a 120mm fan for a cpu i am trying to think of a way of doing that i'v seen the 92mm fans but not 120mm would it make for batter cooling???

there is the ZALMAN CNPS7700-CU.
that has a 120 mm fan inside it ...
http://www.zalmanusa.com/usa/product...45&code=005009