Tweak your CPU!
To tweak our test Celeron we had to flatten and smooth the surface
of the cpu-plate so it would make better contact with our heat
sink. Sanding (or lapping) that plate had the benefit of not
only smoothing the surface, but also polishing it. Polishing would help to
ensures that when the heat sink is attached, the thin layer of thermal
grease on it would easily fill any microscopic voids on either surface,
and also make better contact all around.
Here is a list of what we
used to do this. Keep in mind that if you try this, you can
easily destroy your processor, and Intel's warrenties don't cover this
kind of 'use'.
- Absolutely flat surface (thick glass)
- 600 grit wet/dry sandpaper
- Anti-static foam
- Machine oil
is excellent for smoothing
imperfections in a
We found a surface that was smooth
and absolutely flat - since thick glass (like a table top, or window) generally is, we
used that. A piece of 600 grit silicon carbide sandpaper was placed rough-side up on the
glass and a few drops of oil driped on. The processor was fliped over so that the CPU-plate
was resting on the sandpaper and a small piece of anti-static foam placed overtop of
the pins to pretect them. Pressing down gently, the processor was moved in small
circles, changing direction every few seconds, and turned around every once in a while. This
hopefully stopped any one side from being ground off more than another in the event
pressure was not equally distributed to the back. A few drops of oil were added when
things got dry.
It took us 15-20 minutes before our
test Celeron was ready. We took an extra step, burnishing, then polishing the
CPU-plate. As the sandpaper is worn away, it should be fairly smooth by the end, and
shine up the CPU-plate nicely however.
This picture shows you the minute
differences in hight that existed on our Celeron. Areas in red measured
highest, areas in orange were middleground, and areas in green were
low-spots. The difference between the highest point and the lowest was
Our test Celeron
was measured once more to determine what
impact the grinding actually had on the flatness of the CPU-plate. The center
area (in red) where the processor die is located is the highest spot.The
outside tips were the lowest spots, and the majority of the CPU-plate
is flat to within 0.0005 inches.
Choosing the right heat sink
After all that effort we needed to use the right
type of heat sink. As we mentioned most OEM heat sinks we looked at tended
to bow out in the center slightly. The majority of today's heat sinks are
extruded - molten aluminum is pushed through large steel dies in somewhat the
same fashion as noodles are made. Anyhow, when the aluminum comes out of the die
it is cooled and internal stresses develop as the metal solidifies. That sounds
like a really complicated 10 page explanation, and it is ;-) All you need to
know is those internal stresses warp and distort the heat sink a small degree.
If you have a good steel ruler or something quite straight, hold its edge to the
back of a heat sink, in front of a lightsource and see what I mean. You
will most probably see a splinter of light shine through. If you don't then
you've got a good heat sink and it is quite flat!
That said, we dicided to use the Cooler Master picuted
above. We tested three we had, and two were out of wack, while this one was just
about dead on for flatness - so flatness can vary heat sink to heat sink.
We removed the thermal pad and quickly sanded the bottom (in the
same way as with the processor) to ensure the best possible surface for our
We took our tweaked Celeron and applied a
of Z9-thermal grease (silicon based), and did the same to
the heat sink. Using a piece of old rubber inner-tube to spread the grease around till
it was one uniform layer. I find rubber does a better job of this then
using a finger. The Celeron went into the PPGA-370 socket and the heat
sink went onto the CPU with some even pressure and a twisting motion to dislodge any excess
thermal compound. One thermistor was placed in between the fins of the heat sink overtop of
the center of the CPU, and another between the heatsink and the side of the CPU.
The average of both measurements was used.
We did three types of tests, before the Celeron was
modified and then after. The first test was normal usage, and the second a simulated CPU fan failure for 20 minutes and the third overclocking to
550 MHz - stability was not tested however. Here are the results we got.
||Before tweaking temp
||After tweaking temp
|OC to 550Mhz
The results speak for themselves. Improving the surface
finish and flatness of the CPU-plate (and heat sink), improves the
performance of the computer by reducing the temperature the processor runs at.
The average improvement we saw was about 18%
||This is how the CPU-plate looks
after we 'modified' it. The copper surface is now much smoother, making
better contact with the heat sink. It's also flatter then it was,
increasing the area in direct contact with the heat sink, when the two are
The CPU-plate as Intel ships it - rough, slightly out of
wack, and eager for some tweaking! The
colour is from the angle it was scaned in
The decrease in overall processor operating temperature is significant enough
to make this a worthwhile modification for the Celeron. With better heatsinks
like an Alpha, and case cooling, the temperature of this Celeron certainly could
be brought down even further. While this isn't something for everyone to do, for
those looking for that extra edge in performance, smoothing the kinks out of
your CPU can help to keep things a lot cooler.
||Our test Celeron in its final appearance, with
characteristic copper-top look. Improved performance through cooler running