Fix or replace noisy Micro ATX power supply

April 27, 2017 9:27 PM

This is our noisy Micro ATX power supply in our home made HTPC setup, which is quite the close fit. I think it's this (out of stock) CoolMax 300W power supply on NewEgg. The power supply works, but when the fan spins up, it's really noisy. What's a good replacement power supply for this limited space, assuming we can't make the fan less noisy some way?
posted by filthy light thief to Computers & Internet (5 answers total)

It's possible to replace a PSU fan. There's a good chance your power supply takes a standard 80mm fan.

Caveat: PSUs contain capacitors which can hold enough charge to kill or maim long after they are turned off. Make sure you know what you are doing before opening up a PSU.

Caveat: Coolmax has a reputation for bad quality PSUs. Bad quality PSUs can die and bring your entire system down with them. (See "Tier 5" here. Keep in mind, though, that that list should be taken with a huge grain of salt.) You should probably just replace the whole PSU.

Micro ATX power supplies are known as "SFX" these days (presumably because they work with all modern motherboard form factors, not just the original micro ATX).

The platinum standard for SFX supplies are the SF450 and SF600 from Corsair. (Reviews are from Jonny Guru, the internet's leading power supply reviewer. You'll probably want the 450W version.)

Caveat: there are some slight differences when going from older to newer ATX PSU specifications (mostly the elimination of the -5V rail and decreased 3.3V and 5V rail amperages). Depending on how old you motherboard is, modern power supplies may be incompatible.
posted by lozierj at 10:22 PM on April 27, 2017 [1 favorite]

LozierJ beat me to it as I was typing and makes good points. If you blasted it with air, it may be the bearing. Take the PSU capacitor warning seriously. If your setup is low enough wattage, you could also go the picopsu route, which has no fan. 80 Plus, bronze, gold, and platinum descriptors indicate the level of efficiency, and if this is always on, you can decide which balance of cost/efficiency work for you. In addition to the Corsair models, Seasonic is also a rock solid brand.
posted by palionex at 10:27 PM on April 27, 2017 [2 favorites]

In addition to the Corsair models, Seasonic is also a rock solid brand.

Normally I'd recommend SeaSonic in a heartbeat, but as far as I can tell, they don't seem to have an SFX offering at this time. (Although they do, oddly enough, make an even smaller TFX part.) The Silverstone ST45SF-G gets good reviews in the SFX space, but a lot of complaints about (you guessed it) the fan. So many complaints, indeed, that the "best" SFX power supply according to this HardForum thread, is the ST45SF-G with an aftermarket Noiseblocker PC-P 80x15 fan.

All previously mentioned caveats about the dangers of mucking about in power supplies hold, naturally.
posted by fifthrider at 7:01 AM on April 28, 2017

Response by poster: Thanks for the info on SFX and picopsu power supplies - it's been years since I read up on computer components. The form factor and ability to function in a HTPC (the case is an old stereo tuner, set up in a nook of sorts, so perhaps airflow isn't optimal) are key issues. I'll check out the power specs of my components to see what wattage I need, but I'm 99% sure it's currently a 300W power supply.
posted by filthy light thief at 10:05 AM on April 28, 2017

That motherboard looks like an A785GMH. It supports up to 4 DIMMs of DDR2 and up to an AMD Phenom X4 9950 (140W) (Given the size of your heatsink, it's overwhelmingly more likely you have a ~45W processor in there instead, but this is the worst case scenario.)

I see a 3.5" HDD (call it 7200 rpm even though it's likely 5400 rpm) and a BD-ROM. I can't tell if the incandescent backlight for the front panel is connected, but let's call it a 500 mA USB device. I also see just the one 80 mm fan. Throw in 2 more USB devices, put it all into a PSU calculator, and you're looking at just over 200W max load, which means that a 300W PSU is perfect.

The field of 300W SFX PSUs from reputable manufacturers is pretty narrow. I would recommend the Silverstone ST30SF. That review is for the V1 version. The newer V2 version has a bigger 92mm fan. Like most modern PSUs, it will turn off the fan at idle, which is great for an HTPC. It's a budget model, so the fan is a little noisy under load, the efficiency is high but not amazing and the cables aren't modular.
posted by lozierj at 2:59 PM on April 28, 2017