[luau] Underclocking

MonMotha monmotha at indy.rr.com
Mon Jul 1 13:34:01 PDT 2002


Lots of suggestions for fanless computing (I assume a passive heatsink 
is still OK):

*Watercooling - lets you move the heat out of the system to where a much 
bigger heatsink can be used (or, not very relavent in hawaii, outside 
where temps are very cold, like here in the winter)

*Via C3 - says it needs a fan, but apparently they were designed to be 
used with a heatsink only

*Underclock an OLDER cpu - older cpus made less heat even at full speed 
than recent ones do even when underclocked

*WAAAY underclock a current CPU - My 1.2 tbird even with a very large 
heatsink overheats to thermal shutdown (75C, failure is at 85-95C) in 
~30 seconds from fan failure; you're gunna REALLY have to underclock 
these recent chips

*Use a laptop chip - Intel sells tualatins, which were designed after 
the P4 was made for use in P3m laptops; some other laptop CPUs are pin 
compatible with their desktop counterparts.  These chips are designed 
for lower power consumption and heat dissipation.

You don't mention if you intend to still have case fans or not. 
Remember, your CPU isn't the only source of heat, and good airflow is 
important (CPU will produce heat even if it doesn't need it's own fan 
and that heat needs to go somewhere).  You also need to take into 
account the heat produced the GPU, HDD, PSU, CD-ROM, CD-RW (these can 
make more heat than you'd expect), etc.  Remember, with really good 
airflow (think fan ducting), it is possible to even run a semi-recent 
chip at full speed using just a heatsink (see Compaq, IBM, HP, Gateway, 
etc).  I've seen numerous Pentium IIs and some Pentium IIIs running with 
just a heatsink and using fan ducting to blow air across it.

When considering airflow, remember that you can considerably improve it 
by rerouting cables behind drive cages (45 degree folds will get 90 
degree angles in your ribbon cables.  You can also use round cables. 
You might also consider using pieces of cardboard to create different 
"airflow zones."  For example, you might have the 5.25" bays and PSU 
completely separated from the bottom part, especially if your PSU blows 
hot air inward (as reccomended by the ATX spec) rather than outward 
(what most PSUs do in white boxes).  Also remember that air MOVEMENT is 
not the objective, but rather air FLOW.

Hope these suggestions help.

--MonMotha

W. Wayne Liauh wrote:
> With GHz so inexpensive and so "irrelevant", perhaps the new name of the 
> game should now be changed to "underclocking"--such that we may be able 
> to do away with the CPU fan.
> 
> I have an ASUS K7V333 MB.  I like it very much because, among other 
> things, it is very quiet.  Also it has this "Q-Fan" feature which will 
> automatically reduce the rpm of the fan when the temperature being 
> monitored drops below a threshold value.
> 
> I am thinking about underclocking my Athlon XP 1800+ so that it may only 
> require passive cooling.
> 
> Anyone has any ideas/suggestions?
>




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