Hi all,
I'd like to buy a pc with an Amd 6.4 ghz dual core.
A vendor proposes a system based on the motherboard Asus m2n4-sli
http://www.asus.com/products.aspx?l1=3&l2=101&l3=370&l4=0&model=1266&...
which is fanless.
What exactly is the difference in performance and reliability between
a fanless motherboard and one with a fan, other than noise? How well
does a fanless system dissipate heath and how long can it stay turned
on without damage? I may be saying something very stupid
but does
fanless motherboard imply that the processor, too, is not cooled by a
fan?
The most cpu-intensive task I'll run is video encoding. I'd like to
run videoencoding at night, while I sleep, in the same room where the
pc will be. So I need some compromise between a pc that goes on fire
and one that keeps me awake with its airplane-like noise
Thank you all for your help!
Years ago, the chipset chips, called Northbridge and Southbridge, might
have used 2 watts of power. Some were operated, without a heatsink on
top of them, and used ambient cooling. Some had a heatsink attached, and
a noisy 40mm fan. People discovered that if the fan died, the thing
still seemed to work.
Times have changed. The Northbridge chip can now burn up to 20W of power.
The heatsinks are more substantial. Some chips do get hot. The max temp
on some of them, is 99C. Others have a lower number for their max.
To compare heatsinks, I can show you some performance tables. These are
from the Aavid heatsink catalog. Notice that the heatsink removes 3X
more heat, when 200 linear feet per minute of air is blowing
over the heatsink. The heatsink works much better, when forced
air is applied to it. (These would be examples of older Northbridge
coolers.)
Length Width Height still with
mm mm mm air fan
200LFM
35x35 374624B60024 35.00 35.00 10.00 23.40 7.55 Black anodize
35x35 374724B60024 35.00 35.00 18.00 15.30 5.15 Black anodize
35x35 374824B60024 35.00 35.00 25.00 12.00 4.27 Black anodize
Whether this is important, depends on the final temperature of the
chips being cooled. If the chip went all the way to 100C, chances
are it would be unstable. Maybe it would corrupt some data on a
random basis. If a Southbridge, maybe the SATA port would no longer
work error free.
Some motherboards allow the chipset temperature to be monitored, so
in fact you may be able to see the temperatures involved.
On some Asus designs, a heatpipe is used. This allows the heat to
be moved closer to the CPU cooling device, where airflow spilling
from the CPU fan, helps cool adjacent heatsinks.
In the case of the M2N4-SLI, the aluminum heatsink is far away from
the CPU, so the CPU fan cannot really help it.
http://www.asus.com/999/images/products/1266/1266_l.jpg
If it gets hot, you may need to add a case fan, and point it at the
heatsink. I use such a scheme, as auxiliary cooling for my video
card. So you can fix it yourself, and you can position a fan
near the thing that is too hot.
Fans have an average life of 3 years, some more, some less. For
commercial equipment, part of preventive maintenance may be to
replace the fans at regular intervals, before they fail. So having
a fan present, means there is potential maintenance to do for it.
In a sense, it is "unreliable", because there is a known wearout
mechanism.
You have to balance that, with the impact on the chipset chips themselves.
If operated at high temperature, for extended periods, maybe that
affects the computed reliability as well. But if the chip fails,
then chances are you'd junk the motherboard. (Maybe it is covered
by warranty, but there would be shipping costs etc.) I would suggest
that adding a fan, and maintaining it, may be better than risking the
motherboard itself.
But it is your choice to make.
I use the finger test, as a quick check. If you burn yourself, touching
any heatsink, that tells you something is running too hot. At that
point, I add a fan for sure.
The M2N4-SLI cooler is obviously designed to save money. The motherboard
is likely a lower cost one. So the emphasis is on reducing the
manufacturing cost.
You can read some reviews by customers, for M2N4-SLI, here.
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16813131068
Paul
