"Miki" said:
Following advice of this group I installed passive cooler (Zalman ZM-NB47J).
Now I'm observing the hottest element in an open (!) case is the Northbridge
(especially while I/O operations like disk copyng)
Is it correct? What should be the proper temp. for northbridge? My is so hot
that I can't touch it...
TIA
Miki
From the Aavid catalog, here is some data for some chipset cooling
devices:
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
Basically, that shows a chipset heatsink is three times as effective
if you stick a fan on top of it.
In terms of the equations used to calculate temperature, we don't
know what the power dissipation of the Nvidia chip is. For example,
on the Intel 875/865, power dissipations run around 10-12W and
chip max temp is 99C. If we use the heatsink above with 25mm high
fins, and assume case air temp is 32C (7C above 25C ambient room
temp), the chip temp is 32C + 10W*12.00C/W = 152C and that is
hotter than 99C. If we solve for exactly a 99C chip temp, the
theta in degrees_C/watt is about 6.7 . That means the 18 or 25mm
high heatsink, with a fan installed, would be required.
We can assume the maximum die temperature on the Nvidia chip is
also 99C, but we don't know what the power dissipation rating is.
It might be more or less than 10 watts. I would suggest you get
a 40mm fan and bolt that to the top of your heatsink. Or, arrange
some other fan to blow some air across the fins. An alternate
solution, is put the video selector in 8x/8x mode, and use one
video card. That will mean that half the PCI Express channels will
be shut down, and that could help keep the chip cool. There is
little difference between running a single video card at 16x and
8x, in terms of video performance.
HTH,
Paul
