I Recommend This $100 Fan Mod

The way the HL15 is shipped, it comes with these cg12025m12b2-3y fans from CoolerGuys.com. Problem is that they’re super loud and obnoxious and they had to go. The chassis is designed with only 2 pins wired to all the fans so PWM was pretty much out of the question. I also wanted some blue lights to accent the blue elements of the front panel. I found these fans on sale at my local Best Buy for $15 each.

Thermaltake - Riing 12 LED 120mm Radiator Cooling Fan - Blue

Without the addition of new drivers for a fan or RGB controller, soldering, design changes, or difficulty I was able to get excellent results for under $100.

Temps under full load are under 60C

Google Drive link to a sample of the sound before and after


So how did you connect the fans?

Everyone complains about this, but I don’t think the problem is so much the CoolerGuys fans as it is the chassis wiring/fan hub that keeps them at 100%. I connected the stock fans directly to my mobo headers (not an x11sph if that matters) and they’re fine. Cost me $0.

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The fans are connected to the same headers in the chassis that the original fans were but adding in the “low-noise cable” that throttles the RPM to 1000 instead of the default 1500 RPM.

As @sjenkins mentioned, these connect directly to the existing headers and have Molex if I recall correctly. They’re fixed speed with the ability to put the low-noise cable inline which most likely has extra resistance thus lowering the power applied to the fans. Not unlike how something like a ceiling fan or box fan would use a potentiometer to change the inline resistance to lower the fan speed!

Which is fine, but my point is the CG fans aren’t “loud and obnoxious” if you also run them at 1000 rpm. The mod in this case is then just adding fan speed resistors at $2 ea.

I mean, I don’t care. I usually throw Noctua fans in cases. I just think all these “you have to replace the fans” posts are missing the basic design flaw.


They’re not quite as loud as they run at 1500 not 1800 rpm but I concur that the fan speed extensions are doing the bulk of the work here. The RGB might be worth the upgrade if you’re into that. No RGB or fan controller required with my mod. If you upgrade your CPU though you may have to remove the fan speed reducers which I did temporarily while I waited for an upgraded cooler to come in.

I agree with you. The CoolerGuys fans that come in the HL15 are actually amazing fans! IMO they are only as loud as they are because - like you said - 45Drives did not build out their wiring harness to allow for the fans to run at anything other than 100% all the time. (Bad design IMO)

For anyone else here reading this - unless you are looking to flare up your case with some cool RGB, you just need to find a way that works for your build to calm the fans down a bit when they are not needed. At just a slightly slower speed, the CoolerGuys fans will quiet WAYYYY down and still perform great.

I built a comparison chart with a lot of the popular pro-consumer fans for everyone to compare to.


Can IPMI handle this?

I tried IMPI suggestions first but they only work with PWM fans on the SuperMicro motherboard. I was not able to get voltage control to work on 3pin fans. There are enough headers and the cables are long enough that if you use a PWM fan it’ll work without soldering. But I chose not to go with this solution on the basis of cost. PWM fans run about $20-25 each instead of the $16 each.

Here is what i did to quiet mine: https://youtu.be/6XGb77iiJsk

Dropped about 10db and more importantly lowered the pitch…

Drives and upgraded Xeon 4214 r happy.

TLDR on video, these did the trick: Amazon.com

I have a hard time agreeing with the “bad design” portion. They were chosen with an airflow and thermal load in mind. Fixed speed allows for a drastic cut in cost at an enterprise SMB level. Sure enterprise Dells and HPE’s have variable speed, but their fans are proprietary, exorbitantly expensive, and loud as heck when ramping!

These being 140’s, there’s not a lot outside of consumer fans. I’ve also not seen the airflow and pressure requirements. They also have no idea what we’re gonna stuff in these boxes so it becomes a “we need the most performance per dollar” requirement. I’d rather my fans be loud than my drives overheat. Quite a bit of pressure is needed to get pas the drives and again to help the passive cooler.

Are there better options? Absolutely, but there’s certainly no one size fits all for each individual HL15 out there. Why? Well, because we’re kind of crazy and our homelab boxes turn into a junk drawer of heat producing odds and ends.

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Thanks for sharing, I subscribed after your first (very brief!) HL15 video, excited to see the full series. In this video you describe the fan cables as 47ohm resistors, but link to 27ohm resistors - can you confirm which you actually used?

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Sorry about that, thanks for catching, I updated the link to the 47ohm ones I used.

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Thanks! Just placed an order for 6. I noticed however that my fans aren’t the same as others on the forum, or at least aren’t labeled as such. The FAQ says the full build should include COOLERGUYS fans, but mine are labeled ‘Top Motor’ and seem to have slightly different specs based on some googling. @Vikram-45Drives any insight into why these are different for my build?

I hope these resistors work as well on these fans as they did for you, will report back after testing.

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HI @fred_lab,

I appreciate you bringing this to our attention. I have sent you an email regarding the same. Please kindly reply to the email with your preference so that I can do my best.

Well, after installing the 47ohm resistors on all 6 fans, only 3 of 6 fans were able to start up on their own. After giving two mid-case fans a gentle flick they were able to maintain themselves (so 5/6 fans spinning), but one of the front case fans just wouldn’t spin under its own power. I assume either half the cables are bad, or the voltage is dropping too low for these slightly different fans to get going, @clayd333 did you notice any issues with your install? Any slow or no-starts? According to Vikram, the coolerguys fans are soon being replaced by these top motor fans in all newly built HL15s.

I’ve already started the return process for the resistors and am planning on swapping all the fans entirely. Vikram offered to swap these Top Motor’s for the original Cooler Guys models (thanks again Vikram! you all are awesome!), but if I’m going to swap fans, I’d rather it be for quiet+performant fans.

I’m looking at either the Noctua NF-S12A FLX or the NF-S12A-PWM. I’ve spent some time reviewing other posts on the forum and a super helpful spreadsheet for like-for-like swap options, but the FLX model isn’t included.

It seems to me that the FLX will allow for the ‘cleanest’ install - it will use all of the existing 3-pin cabling, provide nearly equal CFM to stock fans, but at almost 50% lower db while running at the highest RPM (1200), albeit with much lower static pressure. I suppose there’s a little less reusability down the line since they’re not 4-pin, but I’m not planning on swapping any of my full-build gear out any time soon…

@Glitch3dPenguin is there something I’ve missed about the FLX model? Any reason it’s not included in your spreadsheet?

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Thanks for asking. I simply overlooked it as an option. If you’d like shoot me a link to the fan and I’ll add it on the spreadsheet! I need to update it anyway! There have been plenty of new fans that have come out since I’ve made it.


No issues and temps holding solid.

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Sure thing! Here’s the Noctua spec page and the Amazon listing - curious for your thoughts.

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I have added both a 120mm and an 80mm FLX fan to the spreadsheet I have been working on. I use this when looking for fans for my server so I figured I’d share it with the community. They stack up nice and pretty much compete with the other Noctua fans on the list but they knock it out of the ball part when it comes to the noise to CFM ratio.

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