"formerprof" said:
Dear list,
I run an Athlon 3500+ on my A8V. The CPU is under 100% load most of the time
because I am running a heavy-duty number crunchng program. I overclock
mildly -- 3%. The CPU is cooled by the stock AMD cooling fan. According to
ASUSprobe, the CPU temperature is a pretty constant 53 degrees C. I don't
think that's dangerous, but I'd like it to be cooler. I'd very much
appreciate receiving a few recommendations for a superior cooling fan,
bearing in mind that I don't plan to do any substantial overclocking.
Thanks so much.
formerprof
(e-mail address removed) (change the "x" to an "h" for e-mail)
There are web sites that review heatsink/fan combos.
http://silentpcreview.com/section12.html
http://www.overclockers.com/topiclist/index15.asp#HEATSINK REVIEWS AND TIPS
The performance is characterized by a single number, the thermal
resistance thetaR, measured in degrees C per watt of power. If you
have a 0.20C/W heatsink and a 60 watt processor, the temperature
rise is 12 degrees C. If the case ambient is 25C, then the processor
will be 37C. (It isn't really a single number though, as the number
changes with fan speed/capacity. But for a product that ships with
a fan, and with the fan connected directly to +12V, a single number
under those conditions, is good enough.)
Some heatsinks rely on extremely high air velocities to get their
performance. So, the second parameter of interest is the noise
level. Some of the old cooling solutions had a 70dB sound level
caused by a Delta fan spinning at ~7000 RPM. Which means you
couldn't bear to be in the same room with the computer. The best
solutions now, can be almost inaudible when compared to the other
fans cooling the computer.
Be aware that not all the sites measure noise the same way, so the
noise numbers may only be used to compare heatsinks reviewed by
the same review site.
To get the "inaudible" level of performance, requires a footprint
for the heatsink which is larger than the processor area on the
board. In several cases, the heatsink extends outside the
envelope of the motherboard, which means you have to check the
distance between the PSU and the edge of the motherboard.
Clearance from motherboard components (DIMMs, Northbridge heatsink,
any capacitors) and from the PSU, is the hardest part of shopping
for a heatsink. A good heatsink maker will have a compatibility
list on their web site, to help with the selection process.
The bad makers leave the fit issue to your imagination (or to
pictures in a review article).
A good heatsink uses copper in the base, as copper spreads the
heat from the tiny die area, so the heat makes it into the fins.
A bad spreading solution means you have lots of fins, but the
outside fins aren't doing anything. The fins themselves, should
be constructed to have optimal surface area (without becoming
dust traps). The clearance between fins is a measure of the
expected air pressure - a heatsink with a small clearance between
fins, will require a faster fan rate, to generate enough pressure
to push the air through the apertures. So, some of the heatsinks
you will be looking at, are doomed to use a loud fan, to get
decent performance.
You will also see heatsinks with heatpipe technology. A heatpipe
has tremendous theoretical performance. It is vastly more
conductive than a solid chunk of metal. But, one problem with
a heatpipe, is getting the heat into the pipe. There are some
heatsinks, where the heatpipe is joined to the base with thermal
paste, which defeats any benefit the heatpipe might have provided.
Judging by the numbers, most heat pipe applications in computer
heatsinks don't live up to the potential that heat pipes
can provide.
Heatpipes are more or less orientation sensitive.
A heatpipe that uses capillary transport for the working fluid,
is less sensitive to orientation. A pipe that consists of a simple
tube, will only work when it is upright. Since heatpipes
have a fluid inside, and the fluid may be under partial vacuum,
to get a lower boiling point, there is potential for the fluid to
escape at some point in the future, in which case you are left
with only the thermal conductivity of the tube itself. And, in
some reviews I've read, where the heatpipe was sawed open, some
of them have no fluid inside, which is very mysterious.
I would recommend any heatsink that stays close to the motherboard
(no nine inch high assemblies - I hate the tower concept). The
base should be copper and the fins aluminum - that helps to keep
the weight down, so less clamping force is needed, and there is
less stress on the motherboard in the processor area.
The aforementioned Thermalright XP-90 and XP-120 appear to be
well designed. Zalman has the 7000 and 7700 series, and I happen
to like the 7000 AlCu series.
Another aspect of the selection process, is how the product fastens
to the motherboard. The Zalman design uses screws, and that means
no clamps to fiddle with, if reinstalling the heatsink while the
motherboard is still inside the case. On some older heatsinks I've
used, I've used many a fine curse-word, while trying to fit
clamps where you cannot see what you are doing. So, the fitting
process is also a consideration.
And, if you transport your computer a lot, there are some
older heatsinks, where the heatsink is bolted securely to the
board, such that the heatsink cannot fall off. They are a nuisance
to install, but once installed, they can take way more abuse than
the majority of heatsink solutions. See the "crash test" pictures
on this web page
They don't make them like this any more.
http://www.swiftnets.com/products/mcx462plus.asp
Have fun,
Paul
