92mm Fan Recommendation - high speed & quiet

[bhendin]

Hi Guys -

I'm hoping you all could help with some fan recommendations. This isn't an overclock, it's actually a hack done to a server.

I need the following:
PWM fan (needs to be controlled, and report to firmware)
High RPM capacity 4000rpm+ (read below for why this is necessary)
Relatively quiet at speeds of around 1500-2000RPM

Here is the deal:

The problem here is that the server's firmware simply sets its fans to spin at about 30-50% their capacity under normal conditions. The server originally had 6x 6000rpm 92mm fans that usually spun between 2200-2800 RPM. Even at these speeds this thing sounded like a helicopter.

I had replaced the fans with some Scythe Kama fans that had a maximums RPM of around 2500 and rated for good airflow. Putting in the lower rpm fans helped with noise tremendously, however the fans are now only spinning at around 600-800RPM and are having a hard time keeping some components cool (although the overall case temp is good).


I want to replace these again (or at least a couple of them) with some fans that have a high RPM rating. The RPM rating HAS to be high, since the firmware will spin them at a percentage of the rating. Therefore the standard "quiet" fans that only spin at like 2500 or below aren't good enough.

thanks!

 

[holyindian]

I was in ur same delimma two weeks back, and ordered 10 fans of 6 different makes, and returned all except of one.
SilenX EFX-09-15 92mm
http://www.newegg.com/Product/Product.aspx?Item=N82E16835226039

I wanted to test the cfm vs db ratio myself instead. I wanted to add three of 92mm fans to my htpc case for intake, and everyone of them delivered good airflow, but lots of noise as well, but silenx gave the quitest airflow.
I also have two 120mm Scythe Gentle Typhoons in the case, one for exhaust and other for the top ventilation.

 

[bhendin]

Thank holyindian,

unfortunately these are not PWM fans. They also have a max RPM of only 1600, which means they will spin at <= 400RPM in my case, which will certainly not be sufficient.

I realize that cfm is important too, but at 400RPM, the cfm on these will not be sufficient.

I'm having a hard time finding ANY PWM fans that spin faster than about 2500. I may need to try a non PWM fan, which will probably spin at maximum RPM...in which case your suggestion may work.

When I put my last set in, I forgot to connect one of the pwm pins and the server freaked out and spun all the drives to maximum - I need to try setting the alert threshold on that fan to 0 and test again.

 

[holyindian]

High RPM, more noise.
Although the rpm is lower on this fan, but due to the dynamic mechanism of the fans, the air flow is really good.
Sorry abt pwm.. did u look at frozencpu, xoxide or performance pc?

One that comes to mind is.

Delta 90 x 25mm High-Speed PWM Fan - 102.59 CFM 4800 RPM
http://www.frozencpu.com/products/9320/fan-580/Delta_90_x_25mm_High-Speed_PWM_Fan_-_10259_CFM_AFC0912D-PWM_.html?tl=g36c365s940&id=U4eUZrRS

Specification says.
Mfg: Delta
Bearing: 2 Ball - 7 Blade
Dimensions: 92mm x 25mm
Sensor: TAC yes
Connector: 4-Pin PWM
CFM: 102.59 (max)
dBA: 53.00 (max)
Amp: 1.00 (max)
RPM: 4800

P.S. 90mm will fit 92mm

 

[bhendin]

High RPM, more noise.
Although the rpm is lower on this fan, but due to the dynamic mechanism of the fans, the air flow is really good.
Sorry abt pwm.. did u look at frozencpu, xoxide or performance pc?

Yes I know that the higher the RPM, the higher the noise - but that is only if the fan actually spins at that RPM. With most PWM systems you can control the fan speed manually to some degree.

A fan rated at 2000 RPM will most likely not spin that high all the time.

The problem with my server is that the fan speed is unchangeable. It doesn't seem to vary granularly according to system temp.

If the system is running within allowable temp ranges the fans spin at about 30% their max RPM. If the temp range goes about that the fans seem to spin up to their maximum.

My current fans are max 2500RPM, but are currently spinning much lower. Right now they appear to be going at about 1275. But, when it is cooler inside they have fallen below 500.

I think what I need to do is see exactly what the server will do without the PWM connected on a single fan. If it spins up all the fans to 100% then my only option may be to simply not use PWM and put in like 1500RPM fans. That way we will get a constant 1500RPM without adjustments.

Thanks for those links...I'm gonna do some testing and report back