During the last round of home lab host upgrades (post HERE) I moved away from the traditional ATX mid-tower cases I had been using and forewent the current trend of micro-ATX or Mac-Mini/NUC builds (though recently purchased NUC’s for a 2 node management cluster) to use rack mount servers. So far I have no regrets in making that choice as working on the systems as has been for simpler then in the past. Just unhook some cables and slide them out.
The trade off I made for this choice is these systems put off a far greater amount of noise then my previous systems. With 4 x 80MM fans per host only with active CPU coolers they could put off a decent hummm sound. While the systems passed the wife noise factor as the are resting in the garage, the hummmm sound grabbed my attention each and every time I stepped into the garage. It was like my own version of “The Tell-Tale Heart” or at the very least my adult ADHD kicking in.
I set out to do some research to see what options where available to me, and specifically for the SuperMicro server chassis. Hitting the Google’s I am stumbled across SuperMicro’s System Fan Matrix document, located HERE. Since I have model SC822 systems it showed that they are using a standard size 80 x 80 x 25 fan. The stock fan spins @ 3700 RPMs, moves 48.5 CFM of air, and is rated @ 36dBA. From the onboard IMPI interface of my motherboard I could see that my CPU temp hovered around 40 degrees Celsius with the fans spinning at 3000 RPMs.
Now the tradeoff of switching out the stock fans with slower/quiter systems I knew would raise the operating temperature from the current values. That is a tradeoff I was willing to make as I believed the switch in fans would take the system temperature into an error or warning state. Also, with living in Washington, I don’t worry to much about extreme heat in the garage and might only spin the systems down a week or two in the month of August.
With the only other considerations being that the replacement fans had to have a 4 pin power connector and support Pulse Width Modulation (PWM) I took a look at NewEgg to what options where available. I am across the Gelid Silent Series case fan and the specifications looked like a good fit with their air flow being 27 CFM, the noise level at a respectable 21.5dBA, and fan speed of 900 – 2000 RPM. I placed 12 of these into the cart.
Prior to replacing the stock fans in the systems, using my iPAD and a dBA app I took some initial readings to know what I was dealing with. The system as configured was around 45 dBA while being three feet away. With the stock fans replaced with the Gelid Silent Series that number dropped to 32 dBA and the systems are probably quieter then the original ATX cases they replaced. Success!
About Those Tradeoffs
As expected the system temperatures did increase from the 40 degrees Celsius I was seeing with the stock fans. In running this configuration for the last couple days we have bumped the CPU temperature to around 56 degrees Celsius. Still with in the supported temperature range of the CPU. The other tradeoff with replacing the stock fans had to do with connectivity of the fan carrier. As the stock fans are hot swap-able they use a mounting bracket for the fan power cable and a fixed receptacle. The challenge was the new fans weren’t grooved correctly to fit. The work around? The power cords where long enough to bypass the hot plug and just plugged them directly to the motherboard.