Bimmer520

Does anyone have the spec. on thermal resistance junction-case on AMD CPU's? How low can you get the case-cooler thermal resistance with a good heat past.
On my un-lidded Turion the temperature rises 15deg C instantly when applying full load before the heat sink starts to warm up. This can either be caused by high thermal resistance or wrong temperature measurements. Are the Athlons better? How much higher thermal resistance will the lid on a lidded CPU contribute with?
I have ordered a massive cupper CPU cooler I am going to test next. ThermalTake Hammer525 Combo Cool, http://www.thermaltake.com/coolers/c.../hammer525.htm It has a thick cupper heat speader in the buttom and a lot of cubber fins and takes 80mm fans. Weight is over 600g. This should give a much lower thermal gradient in the heat sink than a alu sink have. Massive Alu is just not good for heat spreading. Will also use the best awailable heat transfer past I found(Artic Silver 5). Hopefulle this will reduce the thermal resistance and give me more cooling with the same fan.
My conclution is that all high performance CPU's shoud have a thick Cu heat spreader in the bottom of the cooler. Silver would be even better
What have you experienced on this subject?

logan

unfortunately no i dont have that spec, but i can attest to the better heat transfer of copper than aluminum. i got a new copper HSF and dropped my temps from 52c idle 64load to 35.5c idle and 40c load. and of course this is with as5

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Blue_Fire

i wondered that same exact thing, and although i never really got any specs, i did find out that copper transfers and disperses heat faster because it is a softer metel.

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frostbite

Even if they started making hsf out of silver no one would buy them because of the cost

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logan

yea, at that point you could just go with WC or phase changing....

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Bimmer520

The point is that you still need a good heat spreader if you use water or a peltier element. Cu is one of the best metals for conducting heat. Silver is even better, but of cause much too expensive I still wonder if AMD actually have any official specifications for thermal resistance.

Bimmer520

Aureka! Got my new cooler and heat transfer paste today. The CPU temperature dropped 8 deg celcius! I am using the same fan on the cooler. The massive Cu heat sink realy made a difference, and the silver heat transfer paste helps too.

logan

congrats man, what paste did you use? if it was artic silver then over the course of the next 200 hours those temps will go down as it cures... its great to watch (4-6c sometimes)

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Bimmer520

Yes, I did use artic silver 5. The instant temperature when applying full load rise caused by the thermal resistance is down to 4 degrees. It was 10-15 with the old heatsink and silicone paste.