Magnetic levitation comes standard
My single biggest stumbling block with Corsair's past liquid coolers has been the balance between noise levels and the performance of its included fans. The company's past 120-mm and 140-mm fans emphasized performance over noise levels, and a pair of those fans creates an intolerable racket to my ear at full tilt (as they would need to run while cooling an overclocked CPU, for example). The H115i Pro and H150i Pro take a different approach. The boxes for these coolers call them "low-noise" coolers instead of "extreme performance" models, the tag line attached to many of the company's existing all-in-ones.
To fulfill that mission, Corsair includes a welcome functional change on top of these coolers' bolder RGB LED accents: versions of its superb ML-series fans now come in the box with both of these coolers. I first went in depth with the ML120 Pro RGB trio earlier this year, and I came away thoroughly impressed with them. Even with a relatively low top speed, the ML-series proved more than capable of sticking with or beating out much faster-spinning fans while turning in lower noise levels across the board.
To keep the prices of these coolers reasonable, Corsair stripped the ML-series fans back to their basics. Both the H150i Pro's ML120 fans and the H115i Pro's ML140 fans use plain gray rotors and black PBT frames without any kind of rubber corner padding or other gimmicks. The 120-mm fans on board the H150i have a PWM range of 400 RPM to 1600 RPM, as the ML120 Pro RGBs do, and the H115i Pro's 140-mm fans range from 400 RPM to 1200 RPM. I don't lament the loss of RGB LEDs or rubber pads on these fans so long as their superb noise character remains untouched.
Puzzling out installation possibilities
Many past Corsair coolers used a stock Asetek mounting ring design with several interlocking teeth and slots ringing the cold plate. That system worked well enough in the rare instances where builders needed to swap mounting brackets (like one has to do with the included bracket for AMD's Ryzen Threadripper CPUs), but even though it's designed for easy bracket switches, I had to use an eyebrow-raising amount of force to pop off the stock Intel mounting ring on one of the Corsair H115i coolers in the TR labs. The new four-peg system on the H115i Pro and H150i Pro lets the bracket come free with far less force, so it's a lot more user-friendly.
Builders of AMD systems will benefit the most from this new system. Corsair pre-installs an Intel mounting bracket on the coolers from the factory, so builders pledging allegiance to the blue team don't need to bother with a bracket swap. The downside of the new four-peg system is that only folks building Socket AM4 systems will be able to take advantage of the Hydro Pro-series duo out of the box. Corsair includes full mounting hardware for use with Socket AM4's mounting ears with the cooler, so installing either heatsink on any non-Threadripper system should be a snap.
The problem for Threadripper builders is that the Asetek-compatible bracket that AMD includes in the box with those chips won't fit on the new Corsair mounting pegs at all. Corsair will almost certainly offer a Socket TR4 bracket to those Hydro Pro-series buyers who want to mate their coolers with a Threadripper CPU, but the wait involved with getting one of those brackets is an annoying side effect of buying a more niche CPU than AM4 or LGA 1151 fare.
Thanks to Intel's perennial popularity, builders with any LGA 115x motherboard or LGA 20xx socket will enjoy frustration-free compatibility from the Hydro Pro coolers. Corsair includes a backplate and mounting bolts for LGA 115x systems and mounting bolts for the integrated cooler-mounting system of LGA 20xx motherboards.
I'd devote more attention to actually installing the H150i Pro and H115i Pro on our test system here, but installing these coolers is really so simple that it doesn't merit much explanation. On Intel LGA 115x systems, one simply screws four double-ended bolts into the plastic backplate, sandwiching the motherboard with the four cooler-mounting holes present on those mobos. LGA 2011 and LGA 2066 systems don't even need a mounting bracket—the four included mounting bolts for those sockets screw right into the integrated heatsink mounting system on those motherboards.
Once the base mounting system is in place, one only has to situate the cooler's pump head on top of the CPU before securing it with four large cap nuts. Corsair's hardware is refreshingly finger-friendly, and I only needed a screwdriver to deliver the final twist on the cap nuts. With installation complete, we can see how these coolers perform.