T42 long fan vs T43 long fan

[tim S]

I just received a T43 fan (FRU 26R8197) for my not overheating, but certainly very warm T42.
I recently changed the motherboard from a 32MB GPU to a 64MB version and I can certainly feel real warmth on the underside, plus there is more fan activity.

There are some important differences (I think) between the long T42 fan I had, compared to the T43 fan I received.

1. The long pipe heatsink covers the northbridge chip as well as the GPU.

2. The pipe from the northbridge/GPU is much wider than the pipe on the GPU only fan, which makes sense since
it now has to cool two chips.

3. The northbridge/GPU heatsink is angled downwards from the fan which gets rid of the strange (inefficient?) cooling pad over the GPU. On the new fan heatsink there is only a very thin strip of what looks like clear plastic. Once I get the fan installed I’ll see if removing this strip and adding arctic silver makes it more efficient.

4. The fan hub is bigger than the original which could be a double edged sword. Since the hub is bigger maybe the fan is more powerful? But on the other hand the fan blades are a little shorter, so better or worse I don’t know.

I’ll get the fan installed tonight and I’ll get back with my findings.


Tim S

[lexicon]

CMIIW, are you comparing M10 vs M24?
I would like to know the results too..

[tim S]

I'm sorry but I don't understand!
Who or what is CMIIW and what's an M10 or M24?

Tim S

[ajkula66]

M10 is standard T42 long fan

M24 is standard T43 long fan

What you have received is neither of these, since none of them covers the Northbridge chip.

My presumption is that you have a fan for Intel-based T43, which has that feature.

[tim S]

I didn't know the long heatsink fan, that also covers the northbridge, was for the Intel chipset.
Which begs the question; since the Intel chipset runs cooler (supposedly) than the ATi, will this
fan run into heat difficulties while trying to cool a very hot 64MB ATi GPU as well as a pretty hot
northbridge?

Well I'm the guinea pig, or at least my T42 is, so I'll see how it goes.

Tim S

[tim S]

Here we go!
The fan is in and it certainly does the job. First of all though there are some issues.
First the northbridge is considerably lower than the ATi 64mb GPU, so the heatsink
which is pressing down hard on the GPU, is now too high to rest on the northbridge.
Secondly the heatsink over the GRU is slightly smaller (on 2 sides) than on the long
fan I had, so one would think the cooling capabilities wouldn't be as good as the
original T42 fan.
Now the good!
The laptop is running cooler and the fan is quiet but the volume of air coming out is
greater and COOLER than it was before. Also I'm writing this in shorts, so the laptop
is on my thighs, it's warm but not uncomfortable at all.
My take on all this is that the T43 fan/heatsink, while slightly shorter on 2 sides of
the GPU is almost 3 times the width on one side, coupled with the fact it's really
jammed onto the GPU along with a more powerful fan does a much better cooling job
than the original T42 long fan.
It seems the northbridge is not a (heat) factor and all in all I'm very happy I did this.


Tim S

[tim S]

Following up on the (Intel) T43 fan in my T42.
Long fans have a tin ‘strap’ riveted into the end of the heatsink over the GPU.
One of the keyboard screws went through this applying downward force to the
far end of the heatsink.
My T43 fan doesn’t have this so the only downward pressure is from
the heat pipe itself. Not very much at all!
I tried to solder a “strap’ I had removed from an old fan but, in a testament
to the effectiveness of the heat pipe, it took the heat right out of the area I
was trying to solder, so no go with that approach!
OK start again!
I peeled off the strange clear plastic from the underside of the heat sink, so
at least the copper was in contact with the GPU.
On one of my old long fans the heat pad was very much like modeling clay but
kind of rubbery, and not really stuck onto the heatsink at all.
So I removed it and put it over the northbridge which perfectly filled the
gap there, created because of the height difference with the GPU. And it just might take
a little heat away as an added bonus?
I had an adhesive rubber foot in my box of tricks which, after a little playing around, I
found just the right place for it to apply downward pressure keeping the heatsink nicely
flush with the GPU but without buckling the keyboard.

That’s it….. I’m done!

Tim S

[FTC]

Hi, I also had an M24 running in a T42 for 2-3 years, and can also confirm that the machine (specially the GPU) runs cooler with the M24 than with the M10 fan. However, the most difference is gained by the correct application of thermal grease, making usre that pressure on top of the GPU and CPU is enough and mantaining the radiator fins clean. Now I am back to an M10 on that particular T42 and still running fine.