[SC.LUG] Bill Gates to be Knighted?

[Ian Molton]

On Fri, 30 Jan 2004 14:37:46 -0000
"Rick [Kitty5]" <rick at kitty5.com> wrote:

> John Southern wrote:
> > Surrounded by machines, the real problem for me is noise from either
> > the PSU or even CPU fans.
> > As I do not feel confident about plumbing in a water cooled system,
> > what is the alternative?
> 
> You can get quieter PSU's with variable speed fans (that you can turn right
> down),

Most of those are poor designs (even on Enermax PSUs its a gimmick feature) and the PSUs tend to end up running very hot.

> My best advice would be to lower the voltage your fans run at, best method
> would be some fan speed adjusters thingies,

Even then, only the active type - passive ones reduce torque which is critical when starting if the fan has sucked in a hair or lots of dust (or both).

> otherwise you can get 7V by

See above, AND...

> connecting a fan to both the 12V and 5V lines (as oppose to 12V and GND).

DONT do this. many PSUs are NOT tested against a 5V->12V short and you could end up aplying 12V or more to the 5V line if your fan fails shorted.

not to mention this will introduce a lot of noise between two lines where there wont be any filtering to attenuate it.
 
> A slight drop in RPM makes a massive difference to the noise level yet only
> increases your temps by a couple of degrees.

Some studies show a 2 degree (overall)  rise relative to the normal working temperature increases failure rates by over 20%.

> Try swapping small fans for larger ones (especially 60mm or smaller) you can
> get the same airflow at a lower speed and noise.

Good advice - if you have the space...

> Finally, watercooling has matured a great deal over the last few years and
> will make a dramatic difference to the number of fans you need. There is no
> reason why you could not build a single system to cool several boxes.

Water cooling is overkill, not to mention noisy and prone to leakage.

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