PSU Super Flower Leadex III 850W fan change

[d31ma]

Hi!
In my watercooled system I noticed that most loud place - PSU, by default Super Flower has very weird logic for fan mode, even in ECO fan will spin up and down each few minutes even without load. I wrote message to support, but no luck, they replied that fan logic can not be change, even would be better to have static RPM for always, but it doesn`t work (work with the same way as ECO). And while playing in games I can hear 2 thing: coil-whine from RTX4090 and very loud fan from PSU.

All RPM curve mode depending on temps in PSU, but I did not find temp sensor, so maybe it installed from manufacturers in such weird place that very fast hit each minute?!..

So, almost new psu was upgraded:

Stock fan is 130mm, I did not find any replacement, so decided to use my 120mm favorite Noctua NF-A12, but issue that fan is PWM, but I am engineer

Decided do not put again this plastic cover, because new fan will not blowing air to mesh.

And I am very happy with result

Connected PWM cable to Octo controller and setup curve, but before created virtual sensor that getting wattage from cpu + gpu and will use formula for transfer watt to %.

So, I have in "office work" 400-500 RPM on PSU and my Mora radiator and during playing in Cyberpunk (12600KF+RTX4090) my system load will be 550W and 700-800RPM in PSU, very quiet and no weird logic for fan curve as it used for Super Flower.

 

[joemama]

The fan was probably set to activate simply depending on temperature and your load was just enough to make the temperatures rise above the activation limit without the fan while not enough to keep it above the limit after the fan activates so it just constantly switches between on and off.

 

[Shrek]

Another approach might be to change the case fans so that there is positive case pressure and so air flow through the power supply even when the supply fan was off; this should stop it kicking in at low loads.

It also means you can retain the original fan, as the replacement may not have enough flow for full load.

The baffle was also there for a reason.

The original fan looks like 2 lead, but the replacement was 4 lead (and smaller than the original).

I'm also very confused about the case; does the power supply fan get blocked by the case when closed?

 

[Dr. Dro]

Make sure that your quiet approach can cool it appropriately, though. You're pushing that PSU to the brink with a 4090. It's too much for such a low-capacity unit.

 

[claes]

Yeah the mod is cool but I didn’t realize you had such power hungry components… might want to consider a 1000W unit

 

[d31ma]

The fan was probably set to activate simply depending on temperature and your load was just enough to make the temperatures rise above the activation limit without the fan while not enough to keep it above the limit after the fan activates so it just constantly switches between on and off.

I checked all 3 modes on PSU, all worked incorrectly in my opinion. Previously I had EVGA G2 and had no issue, I used passive mode all time.

Another approach might be to change the case fans so that there is positive case pressure and so air flow through the power supply even when the supply fan was off; this should stop it kicking in at low loads.

It also means you can retain the original fan, as the replacement may not have enough flow for full load.

The baffle was also there for a reason.

The original fan looks like 2 lead, but the replacement was 4 lead.

I'm also very confused about the case; does the power supply fan get blocked by the case when closed?

There is mesh panel. Baffle was to block air to get outside throw the psu mesh, but it worked because fan was bigger, now fan is smaller and static pressure better, it blows air exactly in center of psu. Asked my friend, he made the same changing fan on two another PSU`s, he is recommended to use good 120mm fan with 1000RPM maximum. There is not nessecery to have very powerfull fan - you need just fresh air.

It's too much for such a low-capacity unit.

might want to consider a 1000W unit

This unit can handle 1000W https://www.techpowerup.com/review/super-flower-leadex-iii-850-w/2.html

 

[damric]

Wow I thought I was really pushing the envelope with my LEADEX III 850W. Well it did hard shut down during spikes while I was testing my 6900XT with MPT so
I can imagine a 4090 making it work even harder.

 

[d31ma]

Tell me which one would be better? I think about SE, custom 600W cable for GPU from cablemod with 90 angle already ordered.

 

[Dr. Dro]

I checked all 3 modes on PSU, all worked incorrectly in my opinion. Previously I had EVGA G2 and had no issue, I used passive mode all time.


There is mesh panel. Baffle was to block air to get outside throw the psu mesh, but it worked because fan was bigger, now fan is smaller and static pressure better, it blows air exactly in center of psu. Asked my friend, he made the same changing fan on two another PSU`s, he is recommended to use good 120mm fan with 1000RPM maximum. There is not nessecery to have very powerfull fan - you need just fresh air.


This unit can handle 1000W https://www.techpowerup.com/review/super-flower-leadex-iii-850-w/2.html

Yeah but you're still kind of pushing your luck with 850 W unit whose cooling has been intentionally slowed down to make it quieter and a system such as yours.

I've the 1300 W G2 and my PC can definitely make it work, on a 4080 btw

 

[damric]

View attachment 311429
Tell me which one would be better? I think about SE, custom 600W cable for GPU from cablemod with 90 angle already ordered.

Actually what I would do for now is tune that RTX 4090 for efficiency. I bet if you limit clock speeds to 85% that you will keep 95% of your performance while dropping power draw by 30% or more. The 4090 has a massive amount of compute cores and really they don't have to be pushed to high clocks for very awesome performance.

 

[Pumper]

Could have just switched the fan to silent mode instead (0 or I depending on your needs):

 

[Vya Domus]

I did the same thing also with a Noctua fan but 140mm because the stock fan on my PSU developed a rattle and one thing I was pretty disappointed with it is how loud it is, even at like 60% it's the loudest fan in my system. I control it based on temps max(CPU, GPU).

Btw I recommend you keep that plastic cover thing in there, it's meant to direct the airflow in a certain way, probably fine without but it's there for a reason.