Arctic Liquid Freezer III Pro 420 Review

Final Score: 92 out of 100

When thinking about how to properly summarize the ALF III Pro 420(mm) edition, we are strongly reminded of an old meme: “Same, same… but different”. In this regard, it is different in a good way as the new Pro edition keeps faith with its predecessor’s philosophy but with numerous baked-in improvements which offer tangible improvements. Enough improvements that the distance between this King of AIOs and ‘second place’ is even larger than it has ever been. Put simply, you are not going to get better cooling performance from a single bay 420mm form-factored loop unless you go deep into the custom water loop pool. So if you do not care about the hows and whys, rest assured that if you liked the original A.L.F. III, you are going to love the Pro version, and if you disliked the o.g. ALF 3 you may actually like the Pro. Especially if you are rocking an Intel LGA1800-based system.

Diving in deep, there have indeed been numerous improvements and refinements in a single generation. Enough that while we do think Arctic made the right decision in not going to an “ALF 4” branding, it certainly is enough for a “3.5” moniker. Of these numerous improvements, many stand out, but the foundation upon which it is built is not the slight improvement in the waterblock’s performance. It is not built upon the even better Intel RP-ILM / “contact frame” replacement. No. It is the fans.

Yes. Fans are not sexy. Yes. They are actually fungible goods. Such an easily replaceable component that many overlook the stock fans and their impact on the overall design. With the ALF 3.5… err ALF 3 Pro series, doing so will keep you from truly understanding the hows and whys of ALF 3 Pro’s secret to success. This is not hyperbole, nor exaggeration. The ALF 3.5 is simply the exception that proves the rule (that all stock fans suck and should be yeeted during the installation phase).

Typically, 140mm fans may move more air at a given RPM, but they are not as robust in their (static pressure) abilities as the 120 models. This, in turn, means that certain compromises have to be made in either the radiator’s Folds Per Inch fin array density or in noise. Arctic never compromises on performance, so the original ALF 3’s fan had to run a smidgen on the fast side in order to keep up with the inherent static pressure demands that beefy radiator places upon its fans. Which in turn means the fans are typically going to be either ‘louder’ than if they were on a thinner rad or owners will have to tolerate slightly elevated temperatures. This trade-off is arguably why most companies do not opt for thick rads and instead compromise on performance.

That all changes with the ALF 3 Pro. For the first time, buyers can reliably get darn near silent cooling performance without having to tolerate increased temperatures. Yes, with the ALF 3 Pro, one gains access to the best of both worlds… as even at low RPMs, the static pressure is still so gosh darn high it can be relied upon to get the job done and dusted. Furthermore, the static pressure these fans boast is so high that this is a ‘thick’ AIO that really doesn’t “need” a push-pull configuration. Instead, the ALF 3 Pro 420 edition can make a rather good argument for why the 6-fan configuration’s PITA (and ROI) is not worth it. Now that… that is impressive.

Mix in some low-level refinements to the block’s internals with some nice, overdue, quality-of-life improvements in the installation hardware, and there is a lot to like with this new Pro. To be blunt, the grand total of these improvements more than justifies the ‘Pro’ moniker.

Now… with all that said, the ALF 3 design is not perfect, and while the Pro refines the ALF 3 into a razor’s edge, there are still a couple of underlying issues that have not been satisfactorily addressed. It is quite possible they cannot be, and it will take a full overhaul of the ALF blueprint to “fix” them. For example, the Intel installation has been improved over the non-Pro, but it still is a scary proposition for novices. A simple “click” torque wrench should be at the very least made available as an optional purchase… and really should be included. Once again, not a deal breaker. But something that a “Pro” model should have fixed.

This brings us to the crux of the problem with the ALF 3 design: the “overhang” and the lack of mounting orientation issue. Bluntly stated, this is going to be the deal breaker for many. PCIe 5.0 NVME M.2 drives run hot. Blocking people from using good cooling solutions on their main M.2 port is frustrating beyond belief. This was the Achilles’ Heel of the ALF 3, and it still is with the ALF 3 Pro. Yes. Intel LGA1800 users will go ‘what problem?’ as for many, it has been fixed via the new offset… but it has not been for older Intel systems nor AMD-based systems.

Yes. Arctic offers a free M.2 heatsink. That low-profile M.2 heatsink is simply not good enough for even hot-running PCIe 4.0 M.2 drives, let alone ~10-watt TDP PCIe 5.0 drives. Put bluntly, they must redesign the AMD mounting brackets if they want to make the ‘perfect’ AIO. Until that day happens, Arctic is keeping the rest of the AIO market on life support and losing a good chunk of potential sales due to their inability to fix this self-inflicted problem. Thankfully, more and more motherboards are coming with multiple PCIe 5.0×4 M.2 ports, and simply using a different port is a legitimate workaround. One that negates and even nullifies this concern nicely… but should not be necessary. So please be aware of this issue, and if you want to use both the best AMD cooling solution and the best M.2 drives… You must choose your motherboard wisely.

Taken as a whole, the ALF 3 Pro 420mm is not going to be right for every build… but it will be for a lot more builds than any 420mm AIO has any right being. As such, as long as you can work around the above minor to moderate issues, there is no good reason to look elsewhere. This is the AIO to buy if you truly value cooling performance, overall value, and even low noise. Congratulations, Arctic, for being able to quickly exceed our already elevated expectations.