# How many case fans can i connect to 400w Power Supply?



## Sukhi_B

Hi i was just wondering how many case fans i could use for my CPU with a 4oo watt power supply. They are all antec 80mm fans and are 12v. At the moment i have 4 case fans, 1 processor fan, 1 cdrw, 1 dvd drive and 1 floppy drive. Is this many items safe for a 400 watt Power supply  or will i have to disconnect something i.e. the front case fans? Please can somebody reply back with an answer. Thanx


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## Guest

Hi,

If I understand what you are saying is that you have 4 case fans and the drives you have listed (not fans for them) in your post. If you have four, you are fine with what you have. Case fans don't actually pull much juice, so don't worry about that. I have heard of people on here who have six, seven, or eight fans. Why? Heavens only knows, because I see not reason to do that. If one sets his air flow up correctly, I can see NO reason to have that many. Kind of like thermal paste, too (much paste) many (fans) can be worse than not enough as you get air through the case in a swirling motion instead of a steady front to back airflow. Well, anyway, that is my personal opinion from building computers.


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## Sukhi_B

Hi thanx for your post. I also forget to mention that i have a hdd well obvouisly. Any way so you are saying that my power supply is fine with all these fans and will all the hardware that i am running? Also what would you say roughly the Case and SYS temps are in a computer. My Case temp is currently at 55c and SYS temp is 42c. To me these seem quite high but hey im just a beginner! Also how many fans intake/outtake would you recommend, because weirdly enough i added two more intake fans to my pc after having previous 1 intake fan and the temp has rose by about 1/2c  . So at the moment i have 3 intake and 3 outtake. I may be worrying for no reason as i dont know if the temp of my pc is too high or it may just be fine. So if somebody could please just answer these 3/4 questions i would be very grateful. Thanx for the previous help man. :wink:


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## Guest

Hi,

Normal temps might depend upon what CPU and what motherboard you are running so kind of hard to pinpoint without this info. Here is a general range from an article that I picked up that might help:

Processor state - Idle/Burn (deg C) 
P4 Prescott - 45/61 
P4 Northwood - 30/48 
P4 Gallatin - 32/51


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## cyiwin

Just a note on power, 400W is usually great plenty. There is more to look at than just the amount of Wattage. A cheap 400W power supply should be able to reach 400W but only for short periods of time. I would take a quality 350W over a cheap 500W power supply anytime. Also on fans (or anything for that matter) you can figure out how much wattage each fan pulls by multiplying the voltage by the current. Mine draw .14 Amps so 12V * .14A = 1.68 Watts. I wouldn't worry about them over drawing your power suppy.


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## Grump

Here's a link to a handy little tool: Wattage Calculator

I can't vouch for its accuracy, but it's good for general purposes. In all the years I've used and built computers, I have never had a problem with a name-brand power supply. They usually cost a little more. If you are looking for the cheapest PSU, you'll prob'ly get just what you pay for.

Cooler Master has just introduced a new power supply, called the Real Power 450W. I was able to test this for the company and am using it right now.








Another good power supply is the Enermax Noisetaker 470W -- quiet and power to spare and, like the Cooler Master, it has dual 12V rails for more stable power.








There are other good brands available too. I'm a firm believer in over-kill, so get as powerful a PSU as you can afford. Balance the features with what you need in a PSU -- power output, silence, connectors and style.

Grump


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