Cooler Master V850 SFX PSU Fan Swap

gatebatterycursor

Minimal Tinkerer
New User
Jul 30, 2020
3
8
Hi, this is my first post. I wanted to show a fan swap for this Cooler Master v850 SFX PSU. I looked online before doing this mod and found very limited info on it.
This particular PSU is of interest because it is the highest wattage SFX unit currently available. The 1000W unit from silverstone is double the price and SFX-L anyways.

The version I have with with the update temperature dependent fan curve. The earlier units were reported to be annoying because they ramped the fan from 0 - 100% based on load, but newer units do not have that behavior, so this mod is for the constant low RPM noise. I found that the stock fan on this product is pretty loud at low speeds, especially when I compare it to the Corsair 750W unit I had used previously.

Parts:
  • Cooler Master V850 SFX PSU (make sure its the revised temperature based fan curve)
  • Noctua NF A9x14, I used the chromax black version
  • 2 pin to 4 pin fan adapter. this is the specific product I used.

Disclaimer - Obviously this voids the warranty and its dangerous to poke around the inside of a power supply.

First I unscrewed the top of the PSU and unplugged the original fan. This is a picture of the 2-pin fan connector.
0ajzkgP.jpg


Then I unscrewed the default fan from the top panel and replace it with the noctua fan. They are the same size (92mmx15mm) and no extra work to attach the new one to the top panel. I made sure the corner with the fan cable is close to the corner with the 2-pin fan header. This was important for fitting it together later.

The V850 SFX is very dense and there's not much extra space inside. In order to plug the 4-pin PWM noctua fan to the PSU, I had to use the 2-pin to 4 pin adapter. The connector for this adapter is somewhat bulky, and I had to find a space for it inside the PSU. Luckily, there is this small void right next to the fan header which can fit the connector on the adapter cable.

In this image I am pointing at the location of this void where I had to make sure the connector was stuffed into before closing the unit.

34jiTbB.jpg


Here is the picture of the connection from the fan -> 2 pin adapter. I put electrical tape around it because the fit was loose and actually came unplugged the first time I closed the unit.
VUFsVjO.jpg


By default, the nocuta fan's cable is attached to the outside of the fan's frame by a small plastic tab. This made it impossible to position the connector inside the PSU's empty space. I cut out this tab on the edge to free the cable and get a bit more maneuverability for the cable.

knMrnYu.jpg


Finally, I re-attached the top lid of the PSU. As I am about to close it, I check to make sure the adapter's connector is sitting inside the little void.

2RjjAmW.jpg


When the unit is sealed up, I did one last check to make sure the fan spins freely, and did not get blocked by a cable or the 2 pin adapter's connector.
1kAEdRd.jpg
22OgiRf.jpg


Finally, here is a comparison of the stock fan and the noctua fan.
LlTLxw0.jpg
zl8T5UQ.jpg


Result - I ran furmark to cause the PSU temperature to increase. After some time, the fan seems to spin up just fine. Compared to the stock fan, it is basically inaudible over the rest of my system.
 

OgSecret

What's an ITX?
New User
Jan 20, 2023
1
0
i boght that same psu and that fan noise is so loud. i think i do same mod that u did yours. Thx for sharing this! do you think that i can solder that old cable to new one because i live in finland and amazon was only place i find that adapter and posts are 15 dollars to finland :(
 

Komikaze

What's an ITX?
New User
Sep 22, 2023
1
0

StoicJ

What's an ITX?
New User
Jun 19, 2024
1
0
I did this swap and I can't believe how much of a difference it made.

I had a Noctua NF A9x14 from an unused CPU cooler but unfortunately it's cable was way too long to fit inside the PSU so I ended up stealing another 92mm fan from a BeQuiet cooler that had a much smaller cable. They are both absolutely silent fans and infinitely better than the stock one.

Great guide and thanks for the link to the fan adapter. Works like a charm and my build is so much quieter.
 

Jay85

Chassis Packer
Jan 24, 2023
20
21
Has anyone done the fan swap on the newest ATX 3.0 version with the 12vhpwr connector? I'm guessing its the same as the revised version?
 

Naga2x

What's an ITX?
New User
Apr 3, 2025
1
0
Has anyone done the fan swap on the newest ATX 3.0 version with the 12vhpwr connector? I'm guessing its the same as the revised version?

Maybe a bit late. I just did the change and all seems to work as expected. I used an adapter from AliExpress as I'm from Europe (this one, ordered both types just in case). Used the Noctua NF-A9x14 HS-PWM chromax.black.swap. Total cost, around 25€, total time less than 30 minutes.

Thank you very much gatebatterycursor, you are a savior.

Noise is now amazing, the high pitch of the original fan was driving me nuts.
 

premiahum

Minimal Tinkerer
New User
Aug 11, 2025
3
0
I can’t seem to get this working. My Noctua fan doesn’t want to spin whenever connected to my PSU. I’ve tried a lot of trouble shooting and would like some insight.

the adapter is confirmed to work. Using it paired with the stock PSU fan, plugged into the PSU, it spins up just fine.

the Noctua fan is confirmed to work. Plugging into a motherboard fan header, it spins up normally.

The Noctua fan + adapter work together, using the two paired and plugged into the motherboard fan header, it works great.

for whatever reason, when I plug the Noctua fan into the adapter, and the adapter into the PSU, it refuses to work. Why is that? Is there something I’m missing?
 

HWI

SFF Lingo Aficionado
Sep 6, 2022
101
84
I can’t seem to get this working. My Noctua fan doesn’t want to spin whenever connected to my PSU. I’ve tried a lot of trouble shooting and would like some insight.

the adapter is confirmed to work. Using it paired with the stock PSU fan, plugged into the PSU, it spins up just fine.

the Noctua fan is confirmed to work. Plugging into a motherboard fan header, it spins up normally.

The Noctua fan + adapter work together, using the two paired and plugged into the motherboard fan header, it works great.

for whatever reason, when I plug the Noctua fan into the adapter, and the adapter into the PSU, it refuses to work. Why is that? Is there something I’m missing?
Which adapter and which Noctua fan are you using?
 

ismahell

Minimal Tinkerer
New User
Oct 7, 2025
3
1
Hello, I made the swap for the noctua with adapter but the noise of the fan is still loud, idk what to do :(
 

Strobanoff

What's an ITX?
New User
Jan 23, 2026
1
0
Hello, I made the swap for the noctua with adapter but the noise of the fan is still loud, idk what to do :(
I'm pretty sure the reason why this isn't working for you is that you have the earliest revision that has a problem of ramping up the fan to 100% when in reality it doesn't have to spin nearly that fast. I have that very same revision and it rly is a pain in the ass.

A potential solution I'll try too:

Maybe try and route the 4pin connector of the Noctua 2500rpm fan straight to the motherboard sys_fan connector and put a very forgiving constant rpm for it, like 60% constant. For minimum noise with reliable performance the fan should spin at least 1200rpm, 1400rpm or more would be safer and should be more than enough. The noctua fan isn't too loud at 1400rpm afaik. I think you can also change it to behave based on the GPU heat with Fan Control-software (gpu heat=it's using more power=psu working harder=needs more airflow) but the Fan Control software is not 100% reliable. As a fail-safe base you should do the BIOS fan curve as a constant 60% and then try to fiddle with the Fan Control software. This is what I'll try anyways.

Good luck :)
 

premiahum

Minimal Tinkerer
New User
Aug 11, 2025
3
0
I’m using the adapter mentioned by OP and the Brown 92mm noctua fan.
Weirdest thing is happening. Using the stock PSU fan, it’s turns on immediately after boot. I’ll hot swap the fan while it’s on, and the noctua fan also spins. If I have the noctua fan installed on boot, it will not spin. Eventually, it might? But I have no way to test that. I’ve tested my noctua fan a bunch of times and there is a rare occasion that it will turn on while using it, but I can’t tell why.