Hi everyone,

I wanted to change the fan in my antec truepower quattro 850 PSU. But to match the current max air flow of 44CFM at 40dBA, I was planning on using two fans one inside and one outside the PSU.

These are the fans
2 x be quiet! Silent Wings USC producing max 26CFM at 15dBA

So I have two questions:
1. Were should I put the second fan directly on the outside of where the inside fan is, or on the opposite side in push pull configuration?
fan[fan psu] or [fan psu] fan
2. Will the combined air flow of 52CFM be enough?

Thanks in advance

Dazh

Knowing your full config would help - you could be running a rig pulling 80W idle / 300W load or a 180W / 500W load beast, for all we know. If it's the former (or similar) I'd simply go with a single fan. For a hi-end machine, spending most of its time at load, perhaps 2 fans would be better. If you go with 2 fans the [fan psu]fan approach would be better.

How are you going to control the RPM? Hook both fans to the PSU or use a manual control panel / Fanmate?

Also, CFM and dBA specified by manufacturers are, at best, misleading. When choosing fans for replacement I'd rather try to match RPM (which can be easily measured and confirmed) and A (which is most usually v accurate and just printed on the hub or in the technical spec). Simply see what RPM range your default fan is and at what voltage and try to match a similar one. Good brands to research would be Scythe, Nexus, NoiseBlocker Black Silent, Noctua and - like you said - be quiet! fans. Otherwise you may end up with a Thermaltake fan rated for 17 dB @ 4000 RPM and wonder why it sound like a jet engine @ 12V.

Why are you replacing the stock one, anyway? Is the old one faulty (loud) or not strong enough?

I am replacing it because I want to make my pc totally silent (or very close), the psu fan is the loudest part of my rig.

Mb: Crosshair iv formula
cpu: phenom ii quad 3.4 OC 4.0GHz 1.46V
ram: 8gb (4x2) G.skill Ripjaws 7-7-7-21 1.5V
gpu: ati HD 5870 1GB
psu: antec truepower quattro 850 watt
hd: 1x ssd ocz vertex ii 120gb
1x spinpoint f3 1TB
1x WD 750gb

cpu&gpu are watercooled.

I was planning on hooking one fan up to the psu itself and the outside fan to my motherboard and run it at 70% or something.

Hi, I think your PC can pull quite a lot of w so will need to be careful.
On plus side as is water cooled presumably there is little heat in the case for the PSU to be sucking in?
Flicked through some reviews of the PSU and looks like it does have over-heat protection built in so should shut down before cooking itself. Couldn't tell what sort of fan it has in it.

I have an Antec Signature which is similar in that it's straight through 80mm fan design. The stock fan wasn't bad and could get down to ~750rpm using 4 wire PWM control, but wasn't super quiet at that. I believe it can go all the way to ~4000rpm and must be ear splitting!
I've swapped it for an Arctic Cooling F8 PWM fan, on soft "Acousti" mounts, plugged in to the PSU's header so still controlled by it and with the speed wire lengthened and routed out the PSU.
My Q9400 + GTX260 can pull more than 300w AC and while I think your PC may be able to pull more I think won't be too far away.
The fan in my PSU at idle drops below level where rpm is reported but I suspect it to be ~500rpm, under load it will get to 700~800rpm and with extreme benchmarking I've see ~1000rpm, still well below the fans max of >2000rpm so I think the PSU hasn't come anywhere near it's maximum temperature. (then fan speed is based on internal temp of the PSU, affected by load and air intake temps)

I would think you could duplicate what I've done with an F8 or F8 PWM depending with your PSU needs but would strongly advise being able to read the fan speed and checking it's not getting to close to the fans maximum, ie the maximum temp the PSU wishes to be internally.
Pictures in this thread.

Your 2600rpm fan should also work as long as PSU works on voltage not PWM control. You can't add the fan CFMs together when fans are in series. As the PSU is a restrictive airflow path 2 fans in series will push more air but probably not double. I wouldn't bother with two fans until proved that needed, but sometimes two slower fans can cool better one fast one and more quietly.

Rear of PSU will be very hot environment for fan so bearing type/quality maybe important. Perhaps not sleeve bearing, AC fans are some sort of FDB but still very cheap so who knows how will last - OK so far!

Regards, Seb

I did it replaced it with a noctua NF-R8.

And routed the yellow wire out to my Motherboard. So, the RPM hasn't gone above 900 (the fan max is 1800), which is a good thing right.. only my temps (with external temp sensor) are higher then before (25C before 30C after swap). Shouldn't the RPM go higher? (if only black and red are connected it should be controlled by voltage right?) The ambient temperature is like 4 degrees higher then before the swap could that be the problem?

:thumbs up: congratulations

Temp 30C, is that idle or load, measured where exactly?
What casefans do you have if any and which case. Bottom or top mounted psu?


I suspect those two could very well be related in some way.

Hi Dazh, glad it worked out for you Yes if you have the red/black fan wires connected to the PSU internal fan header it will control the fan speed. You should find it's a little lower at first boot and will rise a bit as PC warms up, should also rise if place PC under stress-test load.
The temps will be higher, you're using a slower, quieter fan that's moving less air. The PSU will be warmer but shouldn't be any problem to it and as the fan is far from maximum speed the temp in the PSU isn't at excessive levels.

Seb