Liquid Cooling Exhibits

Summary

Hot Chips doesn’t just consist of presentations on hardware architecture, although those are the core of what Hot Chips is about. The conference also features stands where various companies show off their developments, and that’s not restricted to chips. Some of those showed off interesting liquid cooling components, particularly in cold plate design.Many of the waterblocks on display use microjets, rather than microfin arrays. Water flows through a manifold at the top of the block, and reaches the cold plate surface through small channels. These channels can be distributed across the cold plate, ensuring cold water supply across the chip.Alloy Enterprises showed a cutaway of an early prototype of a MI350X waterblock. The manifold in the top layer (bottom in the photo) would take incoming cold water. Holes in an intermediate layer allow water to pass through, forming microjets. A bottom layer, not shown, would interface with the chip. Finally, hot water from the bottom layer would be drawn out through tubing and eventually make its way to a heat exchanger.Another advantage is that the jets can be positioned with chip hotspots in mind, rather than uniformly across the chip. Jetcool showed off such a design, with holes for water jets positioned at anticipated chip hotspots. Their “SmartLid” waterblock has non-uniform water jet distribution, seen in the hole placement below. Larger holes on the side let water exit.“SmartLid” goes further too, sending water directly to the die without using a cold plate and thermal interface material. Removing layers improves heat transfer efficiency, a concept that enthusiasts are familiar with delidding. Hitting the die directly with water jets is a natural next step, though one that I find at least slightly scary. I hope that rubber gasket is a really good one. I also hope the chip being cooled doesn’t have any water-sensitive surface mount components too close to the die.It’s also worth noting how small the water jets are. They’re d...