Quieter fan for flex power supply

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silverwolf0

Gawd
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Jan 14, 2004
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I'm trying to find a quiet replacement fan for a 450w flex power supply inside an egpu. It's 40x20mm at 12v. The fan header is voltage regulated and idles at 5v and goes up to 7v. The problem is I've tried two fans now (one is a scythe) and both cannot start at 5v. I can make them start spinning with a little flick but that's not really practical.

I'm thinking of getting the NF-A4x20 5v because I can't find a good fan this size rated at 12v that will reliably start at 5v. But not sure what will happen when the voltage goes above 5v or even to 12v, will the 5v fan explode?
 
You see, this is why I laugh when people proclaim that Thunderbolt 3 and eGPUs are the "wave of the future." Even ignoring the 20% performance loss of any GPU you plug in, it's still a joke.

You are suddenly at the mercy of someone else to design TWO DIFFERENT SYSTEMS to your specs, and they're guaranteed to fall short in it. And since we're stuck in Laptop Land (TM), you're stuck hacking your way through a mountain of restrictions to fix something as simple as a loud PSU fan.

Enjoy fixing your broken system. I'll continue enjoying my three silent PCs that have JUST WORKED for years.

You might find help with this VERY CORNER CASE part replacement, but you will probably have to build soundproofing on the outside of the dock...just like real silent PC cases.
 
12v through a 5v part = death. this the same as the blown fan header thread?
 
I assume the fan header is three-pin, i.e. no PWM? As pendragon points out, a 5V fan driven with 12V supply will probably not survive long if at all. Are you sure you need the fan to spin at 5V? I'm using a Noctua fan on my Corsair SF450 PSU. The Noctua also has a higher starting voltage than the SF450 stock fan, but it hasn't been a problem. The PSU might run a bit warmer at idle than it would otherwise, but it'll ramp up the fan voltage as it gets hotter anyway.
Otherwise: You could try the 5V fan with a low dropout (LDO) regulator. That way, anything above (just over) 5V would be regulated down to 5V. Not entirely sure how these behave if the input voltage is below the output, but I imagine they't either do nothing or output something close to the input, either of which would be okay for this.
Or: Use a small microcontroller (Arduino Nano or similar) to measure the voltage and convert to a PWM signal. More effort obviously, but doable if you'ev done any kind of Arduino stuff before. Probably not worth the effort otherwise.
 
defaultluser said:
You see, this is why I laugh when people proclaim that Thunderbolt 3 and eGPUs are the "wave of the future." Even ignoring the 20% performance loss of any GPU you plug in, it's still a joke.

You are suddenly at the mercy of someone else to design TWO DIFFERENT SYSTEMS to your specs, and they're guaranteed to fall short in it. And since we're stuck in Laptop Land (TM), you're stuck hacking your way through a mountain of restrictions to fix something as simple as a loud PSU fan.

Enjoy fixing your broken system. I'll continue enjoying my three silent PCs that have JUST WORKED for years.

You might find help with this VERY CORNER CASE part replacement, but you will probably have to build soundproofing on the outside of the dock...just like real silent PC cases.
Click to expand...

This is not a helpful response. You could really gain something by paying attention to your tone. I see you're trying to state a position but no need to do it at OPs expense .
 
OP - what about tapping into the GPU fan header? This PSU is only powering a GPU so it stands to reason that as GPU temps increase the PSU load increases as well.

Depending on the GPU it could have a 4 or 5 pin mini connector. Moddiy makes several splitters and adapters that could work .You would just want to make sure the PSU 40mm fan does not connect to the PWM/tach wire or it will mess with the RPM of the GPU fans .
 
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