Daily Archives: 29 March 2005

Blowing Hot Air

Electronics, like most people, hate a lot of heat. Heat
reduces, sometime substantially, the expected life of
electronic components. In fact, given enough heat, almost any
electronic component will immediately fail.

As you may remember, I’ve been searching for a new
CPU fan/heatsink.
This is because of the extremely high temperature readings I
got from the very first time I booted SWMBO new PC
(Pentium 4 2.8E Prescott Core) and the related incessant CPU
fan noise.

It was not unusual for Intel’s CPU monitor utility, which
displays temperature and voltage levels of the motherboard
(in addition to fan rpm), to be constantly going off because
the CPU was exceeding the maximum default temperature of
68°C. I was getting peaks exceeding 72°C (about
162°F). Even at idle (the CPU, not me) the utility
typically reported 59°C (about 138°F). Compare this
to the previous generation of Intel CPUs running at about 30
to 40°C.

I first tried adding more fans to my
Antec SLK-2650-BQE
case, which came with a 120mm rear fan
(not to mention the PSU fan). I installed an 80mm fan in the
side panel duct, and an 80mm front fan. While the over
temperature warnings ended, they were still in the
mid-to-high 60° and the stock Intel CPU fan still made
an awful racket because it was spinning as fast as its little
blades could go.

Hence, rather than waiting for the CPU to expire in a puff
of smoke, or my eardrums to burst from the fan whine, I
decided to purchase a new CPU fan/heat sink.

mentioned before
that it came down to two different
models: ThermalRight XP120 and Zalman CNPS7700-AlCu. In the
end, I ordered a Zalman but the smaller brother of the 7700 –
Zalman CNPS7000B-AlCu
. I got this one because it didn’t
exceed the weight limit of 450 grams for Intel motherboards
and because I could get it from Amazon.com (which is a Better
Business Bureau member in good standing).

In order to install the new fan I, of course, had to
remove the old one. I would like to note here that sharp
metal objects and delicate motherboards and CPUs do not a
good match make. Not that I had any problems mind you ;). In
any case, the old fan and heatsink eventually came off. I
then used rubbing alcohol to remove the excess thermal
grease from the CPU. Most sources warn that you should wear gloves when
coming in contact with the grease so consider yourself

While the new fan is much larger than the Intel OEM one, it
doesn’t have any problems fitting on the Intel
motherboard. But be aware that the outside edge
of the heatsink comes awfully close to the bottom of the
power supply and may be a problem in smaller cases. I’m glad
I got the smaller fan because I’m not sure I would have been
able to fit the larger and heavier
Zalman 7700

Fitting problems aside, getting the new fan screwed down
onto the bracket was harder than it should have been. You
have to tighten down two screws. Each is situated at the
opposite and extreme ends of what can be imagined as a lever.
As you try to tighten the first screw down, the other end
rises. It rises so much it is impossible to get the opposite
screw started unless you are pressing down on it. Hard.
Simultaneously, the whole assembly slides around on the thin
film of thermal grease. Eventually, I got both screws started
(it helps to have three hands) and was able to tighten things
down and closed the case up without causing injury to the
motherboard, CPU, case, or myself.

Everything booted up fine so I guess nothing was damaged.
I was, however, disappointed that under idle, there was no
difference in CPU temperature as compared to the stock Intel
fan. I had seen other reviews in which idle temps went down
by five or more degrees. But I did not find any difference at

However, and this makes be happy, there was a big
difference under load. As mentioned earlier, using the stock
Intel fan, I would get constant over heating warnings when
the CPU temp went over 68°C. This occurred when running
simple, relatively low-intensity applications like Word.

Except for one alarm, when first booting, the temp has not
risen above about 62°C (about 143°F), even when
running multiple applications like displaying a DVD (“Animal
House”), while listening to an AAC (Joss Stone), and editing
a document in Word. I don’t know why I got that first alarm
but I hope I don’t get any more.

Not that everything is perfect, though. The Zalman is
running at about 2,700 RPM. This creates noise. Less noise
than the little Intel fan spinning at the same or higher
speeds, but noise nonetheless. Fortunately, this is not a
MPC that needs to
be silent because it’s sitting in your living room. But the
noise is still something you should think about if your
environment requires silence or if you are particularly
sensitive to noise.

If you are, you are on your own. Perhaps the larger Zalman
will work/fit. Maybe not. If not, other than going to water
cooling, I can’t suggest an answer to how to keep your Intel
Prescott core CPU running cool and fans quiet.