With the new Mac Pro hinted, I hear arguments in favor of water cooled Macs to be the new standard for the Pro lines. Water cooled computers do have advantages over intensive workload; it runs indeed cooler, more silent, and smaller. On paper, water cooling is all-around win-win cooling solution. The arguments, then, often conclude with how a new Mac Pro model must provide for “them” in order for Mac environment to even become a viable competitor in their eyes, and how Apple has not been properly serving real consumers other than the devoted. Needless to say, these ideas are oblivious to Apple ecosystem or walled garden effect.
Water cooling denies any chance of a personalizable product in industrial scale. One of the biggest complaint against the current Mac Pro line was its soldered-in design. Not only that stopped any chance of upgrading RAM or SSD —Mac Pro uses PCI-E SSD, which is nearly proprietary— and left its users with faulty AMD graphic cards. All of these could have been easily avoided, possibly remedied had it not been for soldered-in design. Imagine if Apple had replaced air cooling on trash can Macs; we’d be seeing youtube videos of wet box opening, instead of cooked graphics card.
In fact, air cooling has remained industry standard for quite some time now. Even data centers explicitly use air cooling, while, on paper, water cooling would be more appealing choice. That is because of the industry practice; they’ve done risk-benefit analysis and it wasn’t worth it. To start things off, in an industrial scale, sheer volume and weight of water and the equipments to circulate them means added, if not, custom built, systems and buildings: more work is always more money. Air cooling itself is no longer ‘let’s add more fans till it gets cooler’ practice. Cooling fans engineered with efficiency is easily available and products are made in large scales. Computing chips and equipments are readily designed to take advantage of these new gears as well.
Apple is no different. It may be selling its own hardwares, but Apple is not free from commercially available parts offered at competitive prices. Unless one is genuinely arguing Mac Pro should return to the Power PC era, Apple will not be able to purchase or manufacture chips designed with water cooling in mind. An average consumer can convert his/her PC into a water cooling workstation, but only on one’s recognizance. That being said, water cooling hasn’t become an average consumer product yet because of its irreparable risk. Should any major PC manufacturer decides to go all-in on water cooling, that machine will have to be marked ‘water cooled’ all over the place. Otherwise it would be begging for mishaps during shipping and maintenance, or any sorts of handling.
Which brings me to the next point, Thunderbolt 3. Apple recently started supporting for eGPU through Thunderbolt with the release of High Sierra. Chances are Apple will push for further spread of Thunderbolts. It’s already a messy business to deal with one desktop PC. Imagine the chaos if a workstation is replaced with a laptop with Thunderbolt enclosures; each enclosure hooked up to the computer with its own power supply, a water pump, and a water tank.
In theory, Apple could come up with a proprietary fix for this situation, creating a daisy-chain solution for water pumps. Again the problem is the risk. To what point are we going to allow the users to regulate water right next to electronics? This isn’t some sprinklers wetting newspapers we are talking about. And how well the coolants will be maintained in the users’ hand? Without proper maintenance of pipes, tanks, filters, and pumps, water cooling simply doesn’t work.
Now on the bright side, it is possible for Apple to adopt something like vapor chamber, a liquid cooling solution confined in one unit. Mac Pro’s trashcan design was primarily criticized for relying on one fan. Although the vapor chamber will not magically allow computers to run on one giant fan, it’s easy to imagine Apple adopting more solid cooling system that does not require constant maintenance. In fact, heat pipes are already used in laptop lines, covering most of the board with a couple of fans at most. But at this time, changing air with water and/or mineral oil doesn’t add up.
Note Apr 30, 2022: The post, published on Oct 27, 2017, has been republished for better readability, and has since been retitled from “Water Cooling in Mac Should Never Happen”.