Heatsink replacement

[Matt_H]

I need to reattach the heatsink to my AmigaOne. Having spent my entire life with the cool chips of classic Amigas, or pre-fab PC systems, I've never really done any work with heatsinks before.

The current setup has what I think is a thermal pad stuck to one side of the heatsink, and the other side to the G4. The thermal pad is quite a bit larger than the area which it contacts on the CPU. Is this how it's supposed to be?

If I'm not mistaken, my other option is to use thermal paste. This simply is spread on the heatsink at the point of contact with the CPU, right?

Thanks

[Brian]

The original heatsing/fan is simply not enough to cool the G4 for long streches so a full replace is very recomended. The thermal pads suck ass! On my overclocked K6-2 machine replacing the thermal pad with ordinary (no silver super something) thermal paste reduced the heat from 60C to 49C.

Simply apply ther thermal paste on an even thin layer of the heatsink, then place the heatsing over the CPU and move it around a bit so that the thermal paste get realy even on all survaces and no air is trapped inside. Might sound complicated but are dead simple.

So: Get a bigger and better heatsink and a fatter fan to cool the CPU and use thermal paste.

[X-ray]

@ Brian

I presume if Matt doen't have a clip to fasten down the heatsink onto the CPU, he will have to get thermal adhesive rather than thermal paste? What I mean is, the paste won't keep the heatsink on the CPU by itself, will it?

[Brian]

The thermal paste will not keep the heatsink in place by itself, no. For big heatsinks you will have to get real fixing points for it... unless you're willing to glue the heatsink on the the CPU (I did that on a BPPC040, thermal paste alla around, cleaned up like 3*3mm in each corner and glued it at these points, obviously not recomended for expencive cpu's).

With a small heatsing&fan the thermal paste will help holding these flat against the CPU but it will slide of easily unless you keep it in place with something (on my A4000 with PPC060 I added a heatsing to the 060 and keep it in place with one plastic stripp at the top of the heatsink. Stripp goes through the holes in the board for the PPC heatsing holder and isn't tight on the 060, it just prevents it from sliding).

On my B1260 got a small heatsink, cut of some of it's gills to fit underneath the simm (added electrical tape to prevent shots on the simm) and kept it in place with thermal paste. It did slide some but it was mekanicaly pressed byt the simm so it wouldn't move much even though it sit uppside down in the machine.

[Matt_H]

@ X-Ray

The A1 CPU board has two holes for clips on the heatsink to anchor into. It's secure. :-)

@ Brian

Is the default heatsink/fan really insufficient? I haven't actually touched the chip while it's running (since the heatsink covers it), but the surrounding area is very cool to the touch. The heatsink is 'slightly tepid' at worst. Haven't measured with a sensor, though.

[Framiga]

if the heatsink is only tiepid, it is because the thermal pad doesn't transmit all the heat from he coreCPU to the heatsink.

I've just replaced a "crap" adhesive pad on my Permedia2 (CVPPC) with thermal paste.

BTW- at wich clock and core voltage?

take a look here too:

http://s.guillard.free.fr/OS4/Cooling/

http://intuitionbase.com/static.php?section=notes

[Brian]

@Matt_H

Yes it is insufficient if you run it for long periods of time even in an else well vented chassi. It's just a question of time before it starts making trouble so do something about it... while you still can.