The internet has a good number of posts of people who bought a SuperMicro server chassis and then wanted to quiet it. The 24-bay 846 chassis line used to be recommended and seemingly more readily available, but in recent months that supply has either dried up or gone through a cycle and now the 36-bay 847 chassis is easier to find. Both seem to use similar fans. The recommendations online talk about swapping out the power supply for the quiet version (which is what my chassis has, and I can confirm that the PSU does not contribute noticeable noise). Beyond the PSU, advice ranges from getting SuperMicro's alternate fans (FAN-0104L4, usually found in green housing) to going to extreme lengths of replacing the fan wall with 3D-printed items to accommodate larger, 140mm fans. Some people even tried fans like Noctuas. Virtually all of these posts are 7+ years old, so I wanted to contribute to them with some possible updates and notes.
The path I initially followed was to replace the original fans (FAN-0166L4) with the alternate fans (FAN-0104L4). This wasn't cheap - seven fans ran me approximately $180, buying from an eBay seller based out of China. Posts online painted a mixed picture of what's involved in making the swap, and I felt that none of them characterized what I had to do. The alternate fans' housing is too fat for the fan wall, so it's necessary to remove the fans and place them into the casing that houses the original fans. I did not find any posts mentioning that the original fan housing also will not fit the alternate fans without modification. There is a little groove in the original fan housing that is meant for finger placement when pulling a fan out, and while the original fan has spacing that can accommodate this groove, the alternate fans (and probably any other fan you might want) does not. The groove needs to be removed.
I don't know what tools people might have for this purpose, but I just used regular scissors and a pair of pliers. Get the scissors fitted into position, then use your pliers over the scissor blades to close them. It helps if you either have someone holding the casing, or if you can position this on the edge of something and use your foot to steady it. Some force is required, but the scissors cut through the plastic cleanly.
Unmodified original on the left, modified case on the right.
I cut the minimum necessary to remove the groove - two cuts per fan housing. You'll also need to make two small snips at the top to remove the small plastic bar that prevents the tab holding down the electrical plug from being removed.
No before and after, but you can see that the tab can easily be lifted away and reinserted when ready. There are imperfections in the plastic that might highlight where I made my snips.
The results were decent, but still not quite satisfactory: while there was a clear reduction in volume, even reducing the fan's power to 20% resulted in a very audible hum with a resonance effect. It did keep my drives relatively cool (the majority of drives stabilized in the 36-38˚C range, while two of my drives that tend to run hotter than the others would bounce between 41-42˚C). That said, the casing that these fans came in was beige, rather than green. As I mentioned earlier, this was purchased from an eBay seller based out of China. For all I know, these could be counterfeit fans that are louder than they should be... but I'm not going to go chasing any others.
Since I had modified the fan housing and could mount any 80mm fan into it, I chose a more standard case fan that still advertised being able to generate decent static pressure, but with significant noise reduction: the beQuiet! Pure Wings 2. These fans reportedly generate only 18-19 dBa of noise when running at full speed, and if I calculated it correctly, at full speed they'd generate more airflow and static pressure than the FAN-0104L4 fans running at 20% speed.
This was a failure in multiple ways. Seven Pure Wings 2 fans running at about 50% speed still generated a fairly loud hum with a resonance effect that I don't think was any less audible or noticeable than the FAN-0104L4 fans. Worse yet, they could not generate the static pressure needed to keep my hard drives cool. My hottest drives climbed into the mid-40's before I set the fans to maximum speed; I shut my system down when the hottest drive hit 50˚C. I can only conclude that these fans, and Noctuas, are absolutely not sufficient.
I went back to the drawing board and tried another idea that I had read: removing the three rear fans, and sticking with the four front fans. This, combined with the FAN-0104L4 fans, seems like the best solution. There is still an audible mechanical sound, but the volume is decreased and the resonance within the sound is now gone. This case has been on the floor of my office while I've been tinkering, and the fan noise is very audible from the back and side, but not very audible from the front. When I mount this case into my network rack located in my network closet, I am pretty confident that the fan noise will be a non-issue. Perhaps more importantly, hard drive temperatures remain controlled. Drive temperatures have stabilized where they were with seven fans installed: most drives are in the 37-39˚C range, and the hottest drive fluctuates between 41-42˚C. This is with all fans operating around 20%; once the chassis is tucked away, I'll probably try raising the power to the fans to get the temperatures down a bit further, but I'm content with those operating temperatures. My CPU is cooled with an active cooler, but CPU temperatures and cooler activity also do not seem affected by removing the three closer fans.
TL;DR: if you have a SuperMicro 847 and want to quiet it down, save yourself some time and money and just buy four FAN-0104L4 fans. If you haven't bought the chassis yet, consider going with a consumer-grade NAS chassis, instead. Most consumer-grade chassis designs go up to 20 drive bays, but SilverStone recently released a 24-bay version (model RM43-324-RS). The fans in that chassis are probably still loud, but they're larger (120mm) and there are only three of them. I'm extremely tempted to scuttle my SuperMicro chassis for it, but for all of the futzing I've had to do with this chassis, I've come to really appreciate its design... I'll see how bad the noise is once it's in the network closet.
I hope this is helpful. Whoever may be reading this and feeling frustrated, good luck.
Conectar
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