As we mentioned, the 300R is a steel case, and it certainly feels that way--it’s a solid piece of equipment. The overall theme of the exterior case is mesh, mesh, and more mesh, which adds a little bit of pop to its styling, while also facilitating robust cooling.
Indeed, there are no fewer than seven fan mounts (for 120mm or 140mm fans) on the 300R, each with a metal mesh covering. The top panel has two, as does the side panel, and the back has another. The rest of the back is comprised almost entirely of another mesh grill and perforated expansion slots, leaving the entire design open and breezy. The front panel has a pair of metal mesh fan mounts as well, along with two mesh slits on either side of the case that help the included front-mounted intake fan do its job. There’s also a bottom grill under the PSU, which has a removable dust filter, as well.
Technically, the front panel is removable, which is optimal for fan maintenance or grill cleaning, but it doesn’t come off or snap back on particularly easily; it’ll put up a bit of a fight. (Pro tip: You see those eight hex-head screws on the front panel? They serve no purpose whatsoever except to mar the look of the front panel. Don’t bother rooting around in your tool box for the right Allen wrench, because they can stay put when you’re pulling off the panel.)
The front I/O panel has power and reset buttons, headphone and mic jacks, and a pair of USB 3.0 ports with a corresponding header. Given that Corsair clearly wanted to keep the front I/O panel simple, the two USB 3.0 ports were an excellent choice; there’s really nothing else you need in that space, although a media card reader would have been nice.
The 300R ships with just two fans (front and rear), which are a bit loud with a noticeable whine when under load, which causes one to wonder what sort of noise will come out of this thing when it’s got seven fans running full tilt. Granted, the case design isn't exactly built for noise reduction, but the fan noise is an issue to consider.
The exterior of the 300R is certainly designed well--it's definitely functional (if not a bit plain in the looks department) with the air cooling-friendly mesh design, but the interior is even better and evinces Corsair’s terrific design skills.
First off, instead of cramming the case full of drive bays that will never be used, Corsair put one 5.25-inch bay with three trays up at the top of the chassis and tucked a 3.5-inch bay with four trays down at the bottom, leaving a large, open space in the middle that can handle a graphics card up to 450mm in length. The stock front intake fan fits neatly into that space and delivers a stream of cool air over whatever size graphics card you slap in there.
There's also a huge open cutout behind the drive bays, making cabling a breeze. Further, the CPU cooler cutout on the motherboard tray is one of the largest we’ve seen, allowing us to fit our cooler backplate with plenty room to spare. (It’s unbelievable how many cases have cutouts that don’t actually allow adequate space for backplates.)
The motherboard tray is raised up quite a bit from the side panel, thus
allowing generous room for cabling, and it also has four cutouts (alas,
no rubber grommets) for routing cables around the edge of the
motherboard. Our Gigabyte board actually spilled over a bit into the
cutout areas, but it didn’t occlude the openings to the point of being
The 300R supports ATX and mATX motherboards, and our ATX board fit inside reasonably comfortably. However, there was little room left to maneuver, and connecting the 8-pin power connector and some of the fan headers was rather difficult. That said, the huge open midsection of the case made it surprisingly easy to access the memory, ODD power and data cables, 24-pin power connector, front panel headers, graphics card, and (most of the) SATA ports.