Thermalright Peerless Assassin 120 SE ARGB review - budget CPU cooler brilliance

The Thermalright Peerless Assassin 120 SE ARGB might have a rather overblown and incomprehensible name, but don't let that put you off. This sub-$40 CPU cooler is powerful enough to cool high-end CPUs while remaining reasonably quiet, and giving you an RGB lightshow to boot.

It's a combination that drives this Thermalright design straight onto our best CPU cooler guide, as the top option for most people. It's not going to be for everyone, though, so read on to find out what it can and can't do.

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Specs

Design and dimensions

The Thermalright Peerless Assassin 120 SE ARGB has a design that's about as standard as it gets for this type of cooler. It uses two 120mm fans mounted via spring clips to two stacks of heatsinks, each of which receives heat from six heatpipes that run down to the CPU mounting plate at the bottom.

While simple enough, this style of cooler does inherently take up quite a lot of space. At 155mm tall, it should still fit in most standard PC cases quite easily - unlike the even taller Noctua NH-D15, for instance - but it will take up most of the space above the CPU socket. Likewise, its footprint of 110 x 125mm means it stretches fairly far and wide into the confines of your case.

In particular, the front fan will sit over the RAM modules in most setups, so if your memory has tall heatsinks, you'll either have to swap it for shorter RAM or mount the fan higher up on the heatsink. You can check out our guide to the best gaming RAM to find our favorite options for low-profile memory.

Avoiding this overall bulk is one of the main benefits of AIO CPU coolers and water cooling, as these setups keep the area above your CPU relatively clear. This not only makes for a much tidier-looking system, but also makes several upgrades and other PC tinkering tasks easier.

Nonetheless, the Thermalright Peerless Assassin 120 SE ARGB is certainly no worse than any other dual-fan air cooler of this style.

As for styling, this isn't what you'd call a fancy or high-end cooler, but it has a few touches that slightly elevate its look. The main one is that the top plates of each heatsink stack are colored black, which matches the fans and makes for a slightly more cohesive look than you'd get with plain aluminum plates, when viewed from the top/through a case glass panel. The heatpipes and copper base have also been nickel-plated, giving a more uniform silvery look to the rest of the cooler.

Then, of course, there's the RGB lighting. The four lights are mounted in the central hub of each fan, with the lighting dispersing quite effectively throughout the translucent fan fins, though it's definitely most concentrated in the center of each fan.

To power and control the lighting, there's a second cable for each fan along with the main fan control cable, making for a slightly cumbersome four-cable setup. However, you can at least combine the two fan cables into one connector via an included dongle, leaving only the lighting cables needing to find a separate home each.

The lighting can be controlled via standard ARGB headers on your motherboard, which, depending on your board, may in turn mean you can control the lighting via software such as Corsair iCUE, so that you can sync your fan lighting with the rest of your system.

Overall build quality is decent, with no obvious sharp, unfinished parts, while touches such as the nickel plating elevate this cooler over the very cheapest options. Its base plate isn't polished to a shine but it is smooth and flat.

Installation

The Thermalright Peerless Assassin 120 SE ARGB is designed to work with both AMD and Intel CPUs and is compatible with AM4 and AM5 sockets as well as Intel LGA115X, LGA1200, LGA1700, and LGA1851 sockets. Effectively, that means it will work with any standard desktop CPU from the last few years, with the main exception being support for either AMD or Intel's high-end desktop PC (HEDT) CPUs, such as AMD's Threadripper and Intel's LGA 2011 and 2066 chips.

Otherwise, whichever socket you're using, installation of the Peerless Assassin 120 SE ARGB is simple, though as ever with these tall, dual-fan coolers, it can be a little fiddly and you'll need a long thin screwdriver, such as this one.

The process is easier for both AMD sockets than for Intel ones, as the cooler just uses the standard AMD backplate, so you don't need to access the back of your motherboard.

You just remove the standard AMD cooler plastic brackets from the front, then "fit" the red plastic standoffs over the screw holes before placing the the AM4 metal brackets over these and screwing them down. I say "fit" as this is the main fiddly part of this process, as the plastic standoffs only sit loosely, so they're easy to dislodge - it's not a cooler you'll want to attempt to mount with your PC sat vertically or in any other orientation other than laid completely flat.

The second somewhat tricky bit is then screwing the cooler to the base metal plates. The cooler has integrated fittings, but it takes a bit of force to get them to start gripping onto the brackets, and again, you need a long screwdriver to fit between the two heatsink stacks. Nonetheless, it's still a relatively easy process.

Once the cooler is fully screwed down into place, the fans just clip onto the heatsink. There's a knack to hooking these spring clips onto the fans in the right orientation and getting them to clip onto the heatsink, but once you've learned it to install one cooler, they basically all work the same way.

As for Intel sockets, these require the removal of any existing backplate on the motherboard and fitting one of the supplied plates. The latter just slot into place, with the screw holes poking through the holes in the board, ready for you to fit the rest of the hardware in the same manner as the AMD sockets.

Cooling performance

To test the Peerless Assassin 120 SE ARGB's cooling performance, I installed it atop an AMD Ryzen 7 7800X3D mounted in an Asus ROG Crosshair X670E Hero motherboard, using the board's fan and RGB headers. I then ran several tests using Cinebench's multi-threaded ten-minute stress test to load all cores, testing for CPU temperature and noise level. I also tested the CPU temperature and noise level of the cooler using different motherboard fan profiles, to see how the fan's noise ramps up at various load levels under 100%.

Starting with the CPU fully loaded and the fans at 100%, this cooler managed to keep the eight cores of this 120W TDP CPU at 79°C, showing that it can cope quite comfortably with the heat output of this chip.

In terms of using even more powerful CPUs, the Peerless Assassin 120 SE ARGB is rated to cope with up to 265W of heat output, which puts the likes of the Intel Core i9-14900K outside the scope of this cooler but technically means it should cope with an AMD Ryzen 9 9750X, though it would be at its limit with such a powerful CPU. We'd suggest this cooler is instead best used to cool CPUs with up to 12 cores.

Noise level

At full speed in our 100% CPU load test, this cooler hit 46dB of noise, measured from a distance of 20cm from the top of the cooler in an open case. This is far from a terrible amount of noise, but it's also far from the quietest cooler around. This cooler also stayed at this noise level during gaming sessions.

In terms of how this relates to a normal setup, this resulted in a noise level of 35dB at ear level when sat at a desk with the cooler in a closed case sat under a desk. This was with an ambient noise level of 32dB, so it's noticeable but not awful. Meanwhile, as you'd expect, at idle the cooler is effectively silent from this distance.

In general use, the default motherboard fan profile has the cooler hitting 100% speed at around 70°C, and at 50% speed at 50°C, which results in the cooler regularly ramping up to quite noticeable and slightly irritating noise levels just from small spikes in CPU usage. However, switching to the motherboard's silent profile sets the 100% speed at around 75°C and 50% speed at around 55°C, which considerably reduces the noise, and you can easily dial in a manual profile that reduces the severity of these noise spikes even further.

Ultimately, this isn't the absolute quietest cooler around right out of the box, but with the right fan profiles, it can be tuned to be largely undisruptive while still coping well with CPU heat output.

Price

The Peerless Assassin 120 SE ARGB price is just $39.99, so it's not the absolute cheapest cooler available, but it's very reasonably priced for what it offers. Its size and cooling capacity, along with the inclusion of RGB, nickel plating, and a generally smart (if unflashy) design, easily justify its price.

Alternatives

Noctua NH-D15

If you really want to step up to a truly powerful air cooler that will cope with the most powerful desktop CPUs while remaining impressively quiet, the Noctua NH-D15 is it. However, it costs three times as much as the Peerless Assassin 120 SE ARGB and is considerably larger too. Check out our Noctua NH-D15 review for more information.

Cooler Master Hyper 212 Halo White

If your CPU has six cores or fewer, you can likely get away with an even cheaper and smaller cooler than the Peerless Assassin 120 SE ARGB. The Cooler Master Hyper 212 Halo White is our pick of the best single-fan 120mm air coolers, as it's cheap, looks great, and performs well. Check out our Cooler Master Hyper 212 Halo White review for more information.

Verdict

The Thermalright Peerless Assassin 120 SE ARGB isn't the last word in ultra-powerful, ultra-quiet, or ultra-compact CPU coolers. However, if you're after a cooler that can cope easily with the sorts of sensible CPU options we recommend for most gamers, it's a great choice. Rocking an AMD Ryzen 7 9800X3D or Intel Core i5 14600K? This cooler will tame it with ease.

Crucially, it does this while being incredibly cheap yet offering solid build quality, reasonably quiet operation, and including RGB lighting. Spend more and you can get better-built and quieter coolers, while even cheaper coolers can be had that cut a few more corners. However, for the ideal balance, the Peerless Assassin 120 SE ARGB is hard to beat and becomes our new go-to option as the best CPU cooler for most gamers.

To find out which CPUs we recommend for most PC gamers, read our list of the best gaming CPUs, which includes options for a wide range of budgets all tested to see how they actually perform in the latest games.