Discussion Flex PSU w/ no 40mm Fan

aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110
I'm working on a custom sandwich-style SFF case.

A Silverstone 350w flex PSU will be laying on it's side up against 2x 90mm intake fans. I don't want to hear that screaming little 40mm psu fan on my computer desk. My thoughts are, if I remove the aluminum and plastic shrouds from the PSU (as well as the built in 40mm fan), those 90mm fans should provide more than enough airflow to keep it cool.

Or will they? In my opinion, 2x 90mm fans blowing across the PSU circuitry should outperform a little 40mm exhaust fan.

Need some opinions!

A few side notes:
  • I have no intention of buying a Noctua replacement fan. Those things are expensive AF and I'd rather innovate my own solution, especially if it works even better.
  • FLEX psu is a must, as SFX form factor is too big for what I'm trying to achieve.
  • There's some pics of the naked PSU in this post.
 

warpower

Chassis Packer
Jun 2, 2020
13
5
Thanks, but im needIng about 300 watts.

Other option is the HDPLEX 400W HiFi DC-ATX

https://hdplex.com/hdplex-400w-hi-fi-dc-atx-power-supply-16v-24v-wide-range-voltage-input.html

You can use it with HDPLEX 400W AC-DC adapter




WP
 

aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110

Freeks

Chassis Packer
Apr 7, 2018
19
16
I got the same PSU and replaced the fan with a Noctua NF-A4x10 FLX which is quite silent but then also added the low-noise adapter.
The case blocks the top-vent so the air gets pushed out on the cable-side and i can still feel a slight breeze.
My system should take up to 250w on full load and the psu does not seem to get more than warm in this configuration.
 

warpower

Chassis Packer
Jun 2, 2020
13
5
Thanks for the feedback. It really is an awesome solution, but together (if I'm looking at this right) that's over $200 bucks.. to provide just 400 watts. That's a scary dollar to watt ratio!

Sorry for asking but... do you really need a 300W PSU?

I have this system:

Chassis: Streacom Fc9 Alpha (plus ht4 thermal riser)
Motherboard: Asrock B550 Phantom Gaming ITX/ax
CPU: AM4 Ryzen 7 3700X 3,6 GHz 65W
Memory: 32GB Kit Corsair Vengeance LPX DDR4-3200 DIMM CL16
SSD1: SAMSUNG - SSD 970 EVO PLUS 500Gb
SSD2: WD Blue SN550 1T
GPU: ASUS - GeForce GTX 1650 Low Profile OC edition 4GB GDDR5
PSU: Streacom ZF240


So far I've only reached 144W of power consumption.

Can you read your power consumption?

You will probably be surprised with your results.

All the best

WP
 
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aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110
Sorry for asking but... do you really need a 300W PSU?

I have this system:

Chassis: Streacom Fc9 Alpha (plus ht4 thermal riser)
Motherboard: Asrock B550 Phantom Gaming ITX/ax
CPU: AM4 Ryzen 7 3700X 3,6 GHz 65W
Memory: 32GB Kit Corsair Vengeance LPX DDR4-3200 DIMM CL16
SSD1: SAMSUNG - SSD 970 EVO PLUS 500Gb
SSD2: WD Blue SN550 1T
GPU: ASUS - GeForce GTX 1650 Low Profile OC edition 4GB GDDR5
PSU: Streacom ZF240


So far I've only reached 144W of power consumption.

Can you read your power consumption?

You will probably be surprised with your results.

All the best

WP

ryzen 5 1600 (128w max)
zotac 1660ti (125w max)
1tb nvme
4x 92mm fans

And lets be honest, companies SAY their psu's provide so much juice, but that's typically max output on a good day with the fan on turbo. 300 would be ideal. And I refuse to underclock, for the simple fact that it bugs me that I paid for performance I'm not using.
 
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aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110
I bought one of these http://athenapower.com/node/572 for $48 shipped. Should be arriving later this week.

I looked up fan airflow volume for those tiny 40mm fans. less than 10m3/h (5.5 cfm)!
The 92mm fans that will be right up next to the PSU push 7x that amount of air. All I gotta do is remove that noisy 40mm fan and some of the housing on the PSU to let air pass through and I should be golden.
 

Diamorif

Cable-Tie Ninja
Jun 9, 2020
202
96
check out the metalfish 500w modular. Not the best quality, but fine so far. fan is loud, but the only real way to deal with the fan noise on the flex atx psus is the noctua mod. there may be some other fans if you don't want to pay for the Noctua.
 
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aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110
check out the metalfish 500w modular. Not the best quality, but fine so far. fan is loud, but the only real way to deal with the fan noise on the flex atx psus is the noctua mod. there may be some other fans if you don't want to pay for the Noctua.

Decent price for sure. Weird seeing that much wattage on one rail. I'll keep it in mind if this Athena doesn't work out.
 

Valantar

Shrink Ray Wielder
Jan 20, 2018
2,073
2,049
ryzen 5 1600 (128w max)
zotac 1660ti (125w max)
1tb nvme
4x 92mm fans

And lets be honest, companies SAY their psu's provide so much juice, but that's typically max output on a good day with the fan on turbo. 300 would be ideal. And I refuse to underclock, for the simple fact that it bugs me that I paid for performance I'm not using.
PC PSUs are rated for continuous output, at least the ones compliant with the ATX spec. That means peak output is higher than the rating by some unknown amount. Though you can of course find garbage quality PSUs that fail well below their rated output if you really try. The HDPlex can absolutely deliver the full 400W. MeanWell's AC-DC units have explicit continuous output ratings for both passive and active cooling setups, the latter of which is the number in the name. Not to mention that the power draw numbers you listed will never happen at the same time unless you're doing CPU+GPU rendering or a similar workload - games don't load the CPU to 100% for any significant period of time. I would be surprised if your PC used much more than 180-190W while gaming.
 
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aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110
PC PSUs are rated for continuous output, at least the ones compliant with the ATX spec. That means peak output is higher than the rating by some unknown amount. Though you can of course find garbage quality PSUs that fail well below their rated output if you really try. The HDPlex can absolutely deliver the full 400W. MeanWell's AC-DC units have explicit continuous output ratings for both passive and active cooling setups, the latter of which is the number in the name. Not to mention that the power draw numbers you listed will never happen at the same time unless you're doing CPU+GPU rendering or a similar workload - games don't load the CPU to 100% for any significant period of time. I would be surprised if your PC used much more than 180-190W while gaming.

Yeah, I guessed around 175w during an unstressed 1080p@60 gaming sesh. But I love to push my gear. I don't buy top-tier components and I don't upgrade very often, so I am constantly pushing my components to the max trying to find that sweet spot in (acceptable) graphics quality, resolution, framerates and temps. And it gets trickier every year as newer and more demanding titles come out. TBH, I'm usually pushing the texture and resolution settings so high that I'll be dipping down to 25-30fps sometimes. I love hearing those fans kick into high gear trying to keep that silicon cool :) Maybe it's just the motorhead in me. As for the PSU, I've been looking for a Flex psu under $80 that wouldn't have any overdraw shutdowns while pushing full utilization. Lets hope this new one is up to the test.
 
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devolv

Trash Compacter
Feb 5, 2020
53
38
I bought one of these http://athenapower.com/node/572 for $48 shipped. Should be arriving later this week.

I looked up fan airflow volume for those tiny 40mm fans. less than 10m3/h (5.5 cfm)!
The 92mm fans that will be right up next to the PSU push 7x that amount of air. All I gotta do is remove that noisy 40mm fan and some of the housing on the PSU to let air pass through and I should be golden.
If this FLEX PSU uses a FLX or PWM Fan inside, removing it will be problematic as it'll basically refuse to turn on without the fan running.

As for fans moving air in the case, it's different than a 40mm fan that's specifically moving air from the transformers, coils and capacitors inside a PSU which will cause it to overheat. I understand going silent as I'm pretty sensitive to noise, but a 300W 1U FLEX power supply will almost always require some active cooling. I have modded a Delta 400W unit and replaced it with another 40x15mm fan that span at a reduced constant speed which is virtually silent. However, because of that, I had to reduce the power footprint of the components by undervolting both the GPU and the CPU as a precaution to prevent it from overheating.
 
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aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110
If this FLEX PSU uses a FLX or PWM Fan inside, removing it will be problematic as it'll basically refuse to turn on without the fan running.

As for fans moving air in the case, it's different than a 40mm fan that's specifically moving air from the transformers, coils and capacitors inside a PSU which will cause it to overheat. I understand going silent as I'm pretty sensitive to noise, but a 300W 1U FLEX power supply will almost always require some active cooling. I have modded a Delta 400W unit and replaced it with another 40x15mm fan that span at a reduced constant speed which is virtually silent. However, because of that, I had to reduce the power footprint of the components by undervolting both the GPU and the CPU as a precaution to prevent it from overheating.

PSU came in Thursday, but the inlaws came down Thursday as well and are staying the entire weekend. Dangit!!

I did manage to test the unit though. Benchmarked CPU/GPU independently AND in concert. PSU handled both tests just fine. Though that 40mm sounded like a hair dryer.

I gutted the unit and pulled the fan. Any idea what the internal plastic shroud is for? Im guessing it has some electrical isolating/insulating use, like preventing current arcs to the housing?
 

sp1der

Efficiency Noob
Feb 2, 2020
7
5
I swapped my 400watt flex PSU with a NF-A4x10 FLX.
It runs at full rpm and I can't hear any fan noise at all.

I am a fan noise-sensitive person, go for the swap you won't regret it.
Did the exact approach like the link you have shared. But I did tape up the gap due to my original fan is 15mm in width.
 
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aromachi

SFF Lingo Aficionado
Original poster
Dec 18, 2019
111
110
I swapped my 400watt flex PSU with a NF-A4x10 FLX.
It runs at full rpm and I can't hear any fan noise at all.

I am a fan noise-sensitive person, go for the swap you won't regret it.
Did the exact approach like the link you have shared. But I did tape up the gap due to my original fan is 15mm in width.
I ended up removing the 40mm fan altogether. Made a mesh case for the PSU and it has been very stable sitting next to the dual 92mm case fans. You can read up on it in the 5L link in my signature.