CPUs may be getting smaller, but they’re not actually getting any cooler. Between AMD’s 32- and 64-core Threadripper CPUs, and Intel’s Core X chips, modern high-end desktop CPUs are producing more heat than ever dreamed of 10 years ago.
To address the heat, most high-end PCs use expensive and complex custom liquid cooling to hit peak performance, or self-contained all-in-one liquid coolers.
Enter IceGiant and its air cooler, based on the old concept of a thermosiphon. The company says it can outperform conventional air coolers and compete with liquid coolers. Before we dive deeper, though, we’ll review the current state of PC cooling.
Custom Loop Cooling: The top of the food chain
At the top of the food chain (outside of exotic cooling for the overclocking sports) are custom loop cooling. Typically a copper water block is placed on the CPU or GPU and hooked up to inlet and and outlet tubes. Liquid (mostly water) is then pumped through the water block and through a radiator. The radiator is essentially a large aluminum or copper-finned box, which has fans attached to it to dissipate the heat. Most custom loops feature either very large distribution blocks or reservoirs to increase the volume of water in the system, which can help buffer high heat.
Custom loops are typically the most effective, but also the most expensive and difficult to build with. For those who are averse to mixing water with electricity, they’re also the most risky due to the amount of water (even though it’s typically non-conductive) and the fact that you have to design and assemble it yourself.
All-in-One Cooling: Cost-effective leader
While custom loop cooling works well, it’s been too expensive and too complex for most mainstream users. Instead, many DIYers and PC makers have turned to much simpler All-in-One cooler systems (also called closed-loop coolers), which contain the water block, pump, and radiator in a sealed package that’s easy to install in any PC. On the performance front, a well-designed AiO can compete with some custom loop setups up to a certain thermal limit.
In the vast majority of gaming and performance desktops, AiO coolers have become the prevalent method due to their cost and efficiency. The biggest negatives to AiO systems is still the risk of failure (typically the water pump), as well as leakage from a break in a joint, and the inability to be serviced. AiO are sealed, but over time (years typically), liquid levels can drop as the water molecules pass through the tubing.
Air coolers: Cheaper, more “reliable”
Most basic consumer desktop PCs CPUs are cooled using blocks of aluminum with extruded fins to increase surface area. These simple coolers are sometimes beefed up when needed by using a copper center slug, which conducts heat better than aluminum. Air coolers all work the same way: The aluminum or copper bodies act as head conductors from the hot CPU to the fins, where a fan forces air through them to dissipate heat.
While the basic aluminum air cooler can work for a low-power CPU such as an Athlon or Core i3, higher-end CPUs need higher-end cooling. In air cooling, that’s typically meant moving from simple aluminum or copper conductors to heat pipes.
Heat pipes work by sealing a liquid—usually water—inside of a metal (usually copper) tube. The tube is typically pressed into a metal block or pressed flat to make direct contact with the CPU. As the water is heated up by its proximity to the hot CPU, it changes from liquid to steam and travels through the tube to the colder section, where fins and fans attached to the tube cool it off and it reverts or condenses back to its liquid state. Once cooled off, the liquid travels along a wick (which is typically fins), mesh, or a compacted or “sintered” powder that lines the inside of the heatpipe, back to the CPU. The liquid moves along the wick through a capillary process, which is similar to how water moves though a paper towel when you dab a corner of one into a cup of water.
Heat pipe-based coolers are so effective that they have replaced simple conduction air coolers in all but the cheapest PCs today. The very best air coolers can rival many All-in-One coolers in performance, too. Heat pipes do, however, have a limit, and that’s where IceGiant hopes to step in.
Got all that? Let’s finally dig into thermosiphons on the next page.