Will it fit · CPU cooler
Yes
The Thermalright Peerless Assassin 120 SE is 155 mm tall and the Phanteks XT Pro Ultra takes air coolers up to 184 mm (29 mm to spare).
| Case's max cooler height | 184 mm |
|---|---|
| Thermalright Peerless Assassin 120 SE height | 155 mm |
| Room left | 29 mm |
| Case type | mid tower |
Case limits from the maker's spec sheet (checked 2026-10-15).
Yes. The Thermalright Peerless Assassin 120 SE is 155 mm tall and the Phanteks XT Pro Ultra takes air coolers up to 184 mm (29 mm to spare).
184 mm for air coolers, and radiators up to 360 mm (360 mm on top).
