[guandi]

I have known about motherboard backside temperatures for years as i have always cut out a section of the motherboard tray to allow fitting mounting plates for waterblocks and changing them quickly during testing.

Most of the heat in this area is radiated from the back of the CPU but there is some from the motherboard itself due to high component count in this area on some boards. As it would be highly inefficient to try and cool the cpu through the motherboard, air gap and plastic of the socket the only way would be to directly cool the back of the chip itself.

There are several ways to go about this each with pro's and cons.

Remove the socket from the board - This would allow free access to the rear of the chip on sockets with "holes" in (462 etc) but it would require a special wire "harness" to link it to the motherboard, this extra wire would however affect the cpu's performance as the wires would add resistance due to their length that would slow the flow of electrons (no matter how thin they are), and as anyone knows the reason they make cpu's circuits smaller and smaller is so that the electrons dont have so far to go, but this has the excellent effect of allowing more circuits in the same space, but i'm rambling, the reason you want to cool the back of a cpu is to squeeze extra power out of it, so the harness would outweigh any other potential gains.

Cool the Socket on the Board - This would eliminate the need for a harness and its problems, and allow for complete socket (939 etc) cooling. the only problems with this is finding a heat conductive material that is completely electrically non conductive and designing a clamping method for the cpu as the socket mechanism would just hamper cooling efforts. then you woul have to cool the socket "block" itself probably with radiating fins from each side cooled by the cpu cooler itself, for other solutions, off the top of my head maybe a small heatpipe loop (passive) attatched to each side or a water loop around the edge of the block (water, of course)

Hole in the Board - yep, have the Motherboard designed to have to have a hole behind the socket, that way you can directly attatch a cooling block to the back of the CPU with sockets with holes in. This of course would require a lot of work redesigning the PCB in that area, as motherboards get more sophisticated they have more layers of circuitry and components in this area, its just like a silicone sammich with everything on it.


So... it probably can be done, but its really just not worth it. Anyone obsessed enough to want to cool the *back* of their CPU would probably already have looked into phase change and pelt cooling, which can bring the entire chip, and even the back of the motherboard down to well below freezing. But in reality, water cooling is enough to get the back of most of my motherboards to a few degree's above room temp.