Thermalright Peerless Assassin 120 SE review

The Peerless Assassin 120 SE is a dual-tower air cooler. It measures 125 mm long, 110 mm wide and 155 mm tall. It comes with two TL-C12C 120 mm 4-pin PWM fans rated at 1550 RPM ±10%.

The socket list covers Intel 115X, 1200, 1700 and 1851, plus AMD AM4 and AM5. That takes in both current desktop platforms named in the specifications.

The strongest evidence comes from Tom's Hardware. With a 200W CPU limit running Cinebench, it recorded an average of 61°C over ambient. Tom's described that as the best result it had seen from an air cooler and seven degrees ahead of DeepCool's AK500. In OCCT at 200W on the default fan curve, the cooler reached 64°C over ambient, again seven degrees ahead of the AK500. Tom's calls it the best-performing air cooler it tested.

Vividrepairs used a Ryzen 7 5800X in a 30-minute Cinebench run. The peak was 73°C, against 88°C for the stock Wraith and about 75°C for an Arctic Freezer 34 eSports DUO. With an i5-13600K in Prime95, the peak was 78°C, against 76°C for the be quiet! Dark Rock 4. So it leads in some comparisons and sits close behind in others.

PCGamesN tried the ARGB variant on a Ryzen 7 7800X3D, a 120W TDP chip, and saw 79°C at full fan speed. One LDLC owner with the BLACK variant and a Ryzen 7 7600X reported peaks of 92°C in a heavy benchmark and around 80°C in general use. That is a single owner report on a different variant, but it shows temperatures depend on the chip and the workload. Owners as a group praise the cooling for the money.

The fan specification gives a rated noise of 25.6 dBA. The fans are 4-pin PWM units.

Tom's Hardware ranked it the second-quietest cooler it tested at maximum fan speed. At 50% fan speed it was quieter than every cooler in that group except the Cooler Master and Corsair AIOs. PCGamesN measured 46 dB on the ARGB variant at 100% load, 20 cm away in an open case. It described that as neither terrible nor among the quietest.

Taken together, the results suggest the fans are best left on a moderate curve. Owners describe it as quiet in normal use, which fits Tom's 50% result.

The cooler is a dual-tower design that stands 155 mm tall. Thermalright advises checking chassis clearance and leaving room for tall RAM. Given the stated height and that advice, check your case's CPU cooler height limit and your memory module height before ordering.

Installation is the weak point in the owner feedback. A PCPartPicker reviewer called it an absolute pain and said it took an hour. Owners more widely describe the process as fiddly. With a dual-tower design and two fans to position, plan to set aside time and fit it before the motherboard goes into a cramped case, if you can.

The cooling results in the Tom's Hardware, Vividrepairs and PCGamesN reviews, plus owner praise for performance for the money, make this an easy fit for mid-range desktop builds on a tight budget. It works best for people who value temperatures and low noise over a quick, tidy install. If your case is small, or you want a simple fit, check the height and clearance figures first.