A couple of questions first. How do you know your CPU temp is 76°F? Second,
is this at idle or at 100% utilization. I ask because I have never seen a
CPU that cool and/or with that little delta T from room temp under even 50%
utilization.

If your room temp is 70°F, then I suspect that the inside of the case is
hotter than 76°F (unless you have made a number of air flow modifications
from a standard case) which would make it impossible for the CPU to be
cooler than the air temperature around it unless you were using an active
cooler.

My case is a full tower with a high performance, 4 inch, power supply fan
blowing air out of the case and two high performance 3 inch fans blowing air
into the case from below creating a positive pressure inside the case. The
delta T from room to inside case temp is usually 5 ~ 8°F. Standard mid/mini
towers that I have tests are usually 15 ~ 20°F.

The tests I referred to earlier have been done on a number of systems over
the last 2 years or so using different CPUs, coolers, cases, etc. with
different cooling configurations. Additionally, the CPU was run for 20
minutes at idle and also at 100% utilization to insure stabilized results.
The CPU temp was measured by a thermocouple on the top center of the CPU via
a small hole in the heat sink to insure the greatest accuracy. Inside case
temperatures were taken in several locations to insure a realistic mapping
of the inside air temperature and gradient.

Speaking of inside case temps, I think it was this mailing list that someone
commented that the case was designed to work with the sides on for best
cooling. This in theory is true. In reality, WRT most tower (all sizes), the
temperature around the CPU cooler is lower if the sides are open because the
usual one fan in the power supply can not flow enough air to keep it as cool
as with out the sides. Even with most cases that have a second fan, this is
true because there are not enough unrestricted air inlet/outlet resulting in
a fan that operates at less than 50% CFM rating and/or actually recirculates
internal air.

I hope this clarifies and enlightens or at least creates a hot discussion
<G>.

Daniel Wysocki
Twin*.*Star Computers
770-498-2582 / 800-816-0663
[log in to unmask]
Fast - Reliable - Wallet Friendly

-----Original Message-----
From: Allen Glenn <[log in to unmask]>


>
>My room temp is 70F and the CPU temp is 76F using zinc compound.
>If I use silver compound how much of a drop in CPU temp should I see?
>

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