Karl:
An interesting experiment. One thing that you don't mention -- how much
did the room temperature change between cover off and cover on? From
what I remember from my heat transfer courses, it's a question of
temperature rise above ambient rather than absolute temperature. In
other words, if your measurements were made in a 20 C room, than they
would be 5 degrees higher in a 25 C room. A 2 C change in room
temperature over a period of time isn't all that much, especially in a
non-air conditioned space. I've seen postings on OC sites where they
claim that they have to turn the throttle back during summer days.
(I'm a case off guy myself, but it has more to do with laziness than
performance. Easier to swap stuff around, and easier to clean the carpet
fuzz.)
-- Carroll Grigsby


"K. Karl Kuller" wrote:
>
>     When something is not logical, I check it out for myself.  Since I have
> never seen any computer case designed to "channel" air flow for maximum
> cooling, I mentally disputed the claims that the CPU runs cooler with the
> case cover on.  To prove that the "opposite" is true and the CPU runs hotter
> with the cover on, I made measurements with and without the cover.
>     My ASUS CUBX motherboard is designed to pick up the signal from the
> heat-sensing diode built into my Celeron II 566 Coppermine CPU and the
> associated software displays the temperature on the screen.
>     With the case cover off, the temperature was 39-40 C (running
> CPU-intensive program that had 98% CPU usage) but, after I put the cover
> back on and ran the computer for an hour with this same program, the
> temperature "rose" to 41-42 C.
>     For those who are playing with overclocking and are concerned about
> heat, forget about the so-called channeling of air flow and leave the cover
> off for most efficient cooling of the CPU.
>     K. Karl Kuller        [log in to unmask]
>

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