The PC-9N uses a railing mount design in place of a traditional motherboard tray.
Lian Li has a new take on the motherboard tray of old. Rather than use a slab of steel with a single CPU cutout, the motherboard tray in the PC-9N features several rectangular cutouts, giving way to what Lian Li calls a "railing mount" design. This is supposed to help with thermal performance, as it allows air to flow up and under the motherboard, and also provides additional cable routing options.
Other specs are less cutting edge. There's room for three 3.5-inch had drives and a single 2.5-inch solid state drive in a tool-less modular drive cage at the bottom that's made of aluminum. Thumbscrews with rubber suspensions secure the drives, and the cage itself can be quickly removed or rotated.
Up on top are three 5.25-inch drive bays, which are also tool-less. Cooling chores are handled by a front-mounted 140mm fan, along with a fan mount for an optional 140mm fan in the middle of the front panel. There's also a rear 120mm exhaust fan that comes standard.
The PC-9N can house CPU coolers up to 170mm (6.6 inches high), video cards up to 430mm (16.93 inches) long, and power supplies up to 300mm (11.81 inches) in length.