AIO (all-in-one) cooler

PC Builds

A sealed, pre-filled liquid CPU cooler that ships as one closed unit — pump, tubing, fans and radiator already assembled — so it installs more like an air cooler than a custom water loop and needs no maintenance. The radiator comes in sizes named for the fans it holds, commonly 240mm, 280mm and 360mm, and a bigger radiator generally cools better and can run quieter at a given temperature. Concrete example: a 360mm AIO needs a case with a 360mm radiator mount, often in the top or front. Buying impact: the make-or-break check is whether your case officially supports the radiator size and mounting position you're buying — measure or read the case spec first — and verify the cooler includes a bracket for your CPU socket.