According to a new paper released at the IEEE Semi-Therm conference, IBM has discovered a way to dramatically improve processor cooling. Unlike some other recent cooling breakthroughs, IBM's discovery appears to be one that should be relatively inexpensive to implement, and could have a significant impact on consumer microprocessors in the near future. Without fundamentally changing the approach to CPU cooling today and without the use of more advanced setups like water coolers, IBM says that they can double CPU cooling capacity while making it easier and safer to do so.

IBM's find addresses how thermal paste is typically spread between the face of a chip and the heat spreader that sits directly over the core. Overclockers already know how crucial it is to apply thermal paste the right way: too much, and it causes heat buildup. Too little, and it causes heat buildup. It has to be "just right," which is why IBM looked to find the best way to get the gooey stuff where it needs to be and in the right amount, and to make it significantly more efficient in the process.

A CPU's heatspreader is normally attached directly to the core by use of a paste or glue that has been enriched with micrometer-sized ceramic or metal particles. These particles then form heat-evacuation bridges between the core and the cooler, and it's these bridges that carry heat into the heatspreader.



Diagram: Layers of cooling. (Source: IBM)

In its current form, the process is quite inefficient: IBM's says that up to 40% of a CPU's total thermal budget (i.e., the cooling capacity available to draw heat away from the core) is consumed by these particles. This inefficiency is made worse because the particles aren't truly spread evenly throughout the paste. Instead, particles clump together, forming what IBM refers to as the "Magic Cross", as shown below at Figure 1. This thickened area is a non-homogeneous mixture of paste and particles that dramatically worsens total cooling efficiency across the core.



Figure 1: the Magic Cross. (Source: IBM)

IBM's solution was to design a series of micrometer-length trenches into the copper cap that sits above the CPU core, as shown in the top diagram ("hierarchical branched channels"). These larger and smaller trenches allow for paste to be evenly distributed at precisely the points where it would normally pile up and form a Magic Cross-like structure. Utilizing IBM's new technology allowed researchers to spread thermal paste into a far more homogeneous and efficient pattern, as shown in Figure 2.



Figure 2: Gettin' groovy. (Source: IBM)

The results are quite impressive. Paste thickness could be reduced by a third, and the pressure required to properly fit a CPU cooler on top of a core was cut in half. All of this, and IBM says that cooling capabilities are effectively doubled.

Manufacturing tools to define the micrometer channels are already in development. IBM offers no specific details on when we might see chips using this new procedure in the wild, but they say that the new technology can be quickly integrated into current manufacturing plants at a low cost and using existing process technologies. Whether or not the AMDs or Intels of the world will buy in remains to be seen, but the potential is undeniable.