Does my PC really need a CPU fan?

[007]

My PC (Pentium3 1Ghz) is pretty noisy because of the fans. Now I've had a look and it has 3, a case, cpu and psu fan.

I downloaded a program called Speed Fan which shows you varies temps and allows you to control the fan speeds, except changing the fan speeds doesn't do anything so maybe my motherboard doesn't support it. :shrug:

Anyway my PC temp is pretty cool, average CPU 33 C and HDD 37 C.
So I thought I'd try unplugging the case and cpu fans to see what the temps would be. It made the PC A LOT quiter and I could only hear the PSU fan, also the temps rose to about CPU 36 C and HDD 42 C, so not much difference

Granted I only left it for about 30 mins just in case it started melting. Now I know Intel CPUs run much cooler than AMD so it's made me wander can I get away with not using those fans?

[movaado]

Yes, you will probably need one for a P3 chip, unless it has a huge heatsink.

You might be ok though, from what you've said it appears to be ok although I'd recommend that you try it again whilst doing some cpu intensive task.

[Way_2_FAT]

With the stock heatsink, ermm no... :nuts:

[KiLeAk]

Those temps are quite low, so download CPU Burn-In

http://users.bigpond.net.au/cpuburn/

And run your CPU at 100% for 30 mins, see how hot it gets.....

[Ds3]

Yeah I'm amazed it stayed at 36 with no fan on. You don't need the case fan granted, not on a low spec non-overclocked system, but you should put the CPU through some stress and see what temp it goes too, I'd expect it to get very hot like that...

[jon bda]

Put the CPU under some stress and then watch the temps rise!. Why not just buy a quieter CPU cooler?, something from Zalman or the like would be ideal for you...replace the case fan with something quieter too...
:) :thumbs:

[IAmATeaf]

Some P3 1GHz machines that I've seen don't have a fan on the heatsink but they do have a shroud that sits over them with a much larger fan in the PSU but you're PC case would have been designed with that in mind beforehand. Chances are that if you took the fan off you'd get instability. Best thing to do that is also cheap is run the heatsink and other fans at 7v to quieten them down. To do this you'd need to connect the fans using the 4-pin molex type connector rather than the small 3-pin connector which they probably currently have. On the molex the yellow wire is 12v, the 2 central black wires are Ground and the red is 5v so you'd wire the fan up so that the yellow/red from the fan goes to the yellow wire on the molex and the ground/black goes to the red wire on the molex. This is what I have done for my system but during the summer months or in the UK summer days I have to revert back to running the fans at 12v. The other way around this is to go out and buy a BayBus fan contoller, this allows you to plug your fans into it and then control individual fans speeds via the BayBus front panel.

[007]

Yeah I guess I should have run it under fall stress to test it properly.

The CPU actually sits next to the PSU fan so that probably keeps it slightly cooler. Also while searching the net I found a site suggesting that you could build a cardboard duct from the CPU to the PSU fan which sounded pretty cool if only I could be bothered. :doh:

It's a shame the SpeedFan software can't control the fans on my PC as that would have been ideal. The fans actually connect direct to the motherboard (on previous PC's they connected to the PSU) so I don't know weather that enables them to be controlled some how? Maybe I'll take another look into it or maybe just replace the fans. :shrug:

The Dell computers I've seen are so silent it's hard to tell they're even on! But to be honest it's only really a problem if I leave my computer on overnight doing something - then it's like sleeping in a helicopter! :brickwall

[ohood]

I'd just replace the fans, I wouldn't take the chance of burning out the PC. Also, try looking into sound proofing the case, not sure how, but there must be a reasonably cheap way of doing it.

[jon bda]

Also, try looking into sound proofing the case, not sure how, but there must be a reasonably cheap way of doing it.

Don't bother to use proper soundproofing, use the rolls of flashing that you can get from builders merchants...
:)

[edenfalls]

...Best thing to do that is also cheap is run the heatsink and other fans at 7v to quieten them down. To do this you'd need to... This works well, but you need to be aware of a few things with it:
-This doesn't work with all power supplies, although it does work with most
-Some people say its not good for the power supply because you're using the +5v line as a ground. I don't know enough about electronics to say if this is accurate or not.
-Not all fans start reliably at 7v, although most will.

You can also run fans at 5v to quieten them, although make very sure your fan will start reliably at 5v before sealing your case back up again after making the change!

Hope that helps! :)

[AndyH]

My P4 2.8GHz Media System runs without a CPU fan.. :)


... until speedfan says its getting too hot, at which point the fan spins up.


But while the machine is idle, it stays well behaved around 35-40 degrees without the fan. Start any kind of process off, especially encoding and the fan stays on until its finished. Speedfan is set to keep the temp under 50 degrees.


This is with a jolly good heatsink on the CPU and a custom aluminium case which itself acts like an enormous heatsink.


Shame Speedfan isn't working for you, if you say the fan is connected to the motherboard then that usually indicates they can be controlled. I guess in your case it just means the speed can be monitored, but not adjusted. :(


Cheers,
A.

[007]

I guess in your case it just means the speed can be monitored, but not adjusted.

Yeah I think's that's the case. Oh well, cheers for the suggestions everyone.

[movaado]

I've been thinking about it some more. We used to sell these fancy PCs at work which bolted on the back on Plasma screens.

Anyway, these used to have a 700-1GHz P3 CPU, relatively small heatsink and no fan on them. The cooling was done by a fan blowing air into the chassis at one end which was near the heatsink.

So I'd say as long as you got air intake into the box you should be ok :)

[DeadKenny]

Shame Speedfan isn't working for you, if you say the fan is connected to the motherboard then that usually indicates they can be controlled. I guess in your case it just means the speed can be monitored, but not adjusted. :(

A lot of the motherboard connectors only monitor, especially in older systems.

[adam.mt]

How many wires go from the fans to the motherboard's connectors? Usually it requires 3 to have fan control (black, red and yellow), if only 2 then you won't get fan control.

[movaado]

The yellow is for measuring speed - to change the speed the voltage (i.e. red wire) has to change. Older motherboards can't change the voltage but can measure rpm ;)