# How many 80mm fans can a 300W power supply handle???

#### Unique

##### Registered
Subject says it all.

Just wanna know how many fans i can run. Was gonna have 7 80 mm fans total. is that to much? or no?

A 300W power supply could probably run about 1,000 fans no problem. Don't worry about the fans - worry about the real power hungry devices that you have like video cards and high rpm disks and so on.

80mm fans are not important in the scheme of things.

WITH ALL THOSE FANS, DON'T FORGET TO BUY A SET OF EAR DEFENDERS TO GO WITH THEM!!

Ya ok cool so with 7 80mm fans and a ATA100 7200rpm IBM 45 gig drive and a SB Live X-gamer Gforce Video card and DVD-rom am I ok on power? could I add 2 more drives to the scheme?

If the system you are asking about is a K7/T-Bird/Duron and the Vidcard is an an original GeForce 256, I've read that a 300 Watt PS is not sufficient. I don't remember where, yet I trusted whom ever brought this to light. A 300 Watt PS doesn't give you "room to grow on" anymore. Hello 350W. Ka-ching!

there is also a 650 watt Powers supply somewhere on the maket, but the prob. is i don't remember where. Try www.plycon.com. Ohh wait one sec....
here is is:
go there and they're reviewing it.
But that just might be a little to much for you.
The Don

Well, the typical 300W PSU puts out around 10A at +12V where some units of higher quality can give you around 12A at +12V. You can calculate P=V*I ==> P=12*10 = 120W which means that the average 300W PSU is really a 120W PSU when it comes to +12V only.

The average 80mm fan on the other hand demands around 2,5-2,7W of power at +12V.

Dividing the 120W of total power with the demands of each 80mm fan, let’s say 120/2,6, you get a number around 46 which is the maximum number of 2,6W fans you can run on an average 300W PSU which powers exclusively these fans and nothing else on +12V.

The same goes on for any type of fan: just read the specs and calculate. For reference, the wattage for Sunon fans is: 60mm ~ 2,4W, 80mm~2,6W and 120mm~6,8W.

Imagine

650 watt??? That might be enough to run a quad-tbird setup...

well............ i have a 300w p/s (it was an extra i had laying around) that just powers my fans. it does 5 of the 80mm fans and 4 of the 120mm fans. then again it just does the fans and nothing else. much cheaper to have 2 of the 300W psu's than one of the 600w babies. all depends on which is the bigger issue, cost or aesthetics.

Unique (Mar 11, 2001 01:55 a.m.):
Subject says it all.

Just wanna know how many fans i can run. Was gonna have 7 80 mm fans total. is that to much? or no?

7 80mm fans is inefficient and I'd advise against it. You can move the same amount of air for half the noise by using fewer 120mm or 92mm fans instead.

DonSandro (Mar 11, 2001 03:51 p.m.):
there is also a 650 watt Powers supply somewhere on the maket, but the prob. is i don't remember where. Try www.plycon.com. Ohh wait one sec....
here is is:
go there and they're reviewing it.
But that just might be a little to much for you.
The Don

Hehehehe...my microwave is only 500W....

I'm not sure if any of you guys realize this, but a 72W peltier draws 120W of current (puts 192W of heat load on the waterblock/heatsink).

So I could see needing a 650W PSU if I had an SMP Tbird rig with a peltier on each CPU.

Nagorak (Mar 11, 2001 11:40 p.m.):
Unique (Mar 11, 2001 01:55 a.m.):
Subject says it all.

Just want to know how many fans I can run. Was going to have 7 80 mm fans total. is that to much? or no?

7 80mm fans is inefficient and I'd advise against it. You can move the same amount of air for half the noise by using fewer 120mm or 92mm fans instead.

I already have the 80 mm fans.

If i where to have only 2 fans on the side panel instaed of the 3 i was gonna have and only 1 for the exhust fan on the top instead of the 2 i was gonna have for as total of 5 80mm fans will that do the job cooling? (coppermine 700E @ 1086mhz)???

Depends... Are these fans any good, or are they just junky "generics"?

I think two on the side would probably be fine. All things being equal, try to balance the amount of intake fans with the amount of outtake fans (also keeping in mind that your PowerSupply has a fan). If you can tolerate the noise with all the fans running, then you'll do just fine. I'm rather intolerate of excessive fan noise, myself, which is why I am always warning people about it ;-)

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