[CUBE] Cube overheats

[Bill Bradford]

On Tue, Nov 26, 2002 at 12:17:43AM -0800, Stephen Maris wrote:
> a comment below about blowing air 'down' the chimney is wrong. this 
> is fighting the natural convection, which causes hot air to rise, so 
> it would be fighting nature.

Say what you may, my tests show the opposite.  My system stays at a
constant 20-24C with a fan blowing air down from the top, versus 
28-32C with a fan blowing up from under the cube:

http://www.mrbill.net/newcam/test/tn/newcam.jpg.html

You can see the ThermoInDock in the Dock in that picture, even.
G4/450, 1.2G RAM, GeForce 2MX video card (with heatsink, and
not a fan; this is a tower-model card).

Any movement of air from "natural convection" is so small as to 
be insignificant - as long as there's "fresh" or "cooler" air 
going through that heat sink in the middle of the Cube, it doesent
matter which direction its blowing from.  The airflow from the fan 
is easily 100x as powerful as any natural convection.

I suspect that my setup works best "from the top" due to there 
being less "interference" - e.g., bigger vents and virtually no
obstructions between the fan and internal heat sink when blowing
down through the vents at the top - but when blowing up from the 
bottom, the airflow hits a sheet of metal with holes in it, rather 
than mostly-open vents.

Perhaps its different with a fan properly internally mounted inside
the cube in the "factory" fan bracket, sucking air from the bottom
and blowing upwards with little/no resistance - but I cant go that 
route and keep my AppleCare (installing a fan voids any AppleCare
warranty).

I've never had heating problems, even with the GF2MX and no 
external fan - but I run the fan to keep the system cool and
help insure long life, as it is my main desktop system right now.

Bill

-- 
bill bradford
mrbill at mrbill.net
austin, texas