Cooler Master MasterBox MB400L Chassis

Building a Gaming PC in 2021 is honestly not the most practical or affordable endeavor, with stock levels at their lowest and pricing at their all-time highest you’re likely to sacrifice in some way to get a decent system for what you’ve budgeted for. Thankfully, decent chassis’ don’t always have to cost you a fortune, that is if you’re willing to compromise on size. Enter the Cooler Master MasterBox MB400L Chassis, a small-ish case that fits both ITX and mATX Motherboards as well as full sized GPUs. The MB400L comes in at 411 (l) x 218 (w) x 410 (h) millimeters and features a brushed metal solid front featuring a simple CM hexagon logo with side mesh intakes, a tempered glass side panel and clean PSU shroud with space for 2x 3.5″ Drives and 2x 2.5″ Drives. A nice touch is the inclusion of a removable dust filter at the bottom with four rubber feet to give just enough clearance for PSU ventilation.

While the front of the chassis may not have the best airflow possible due to the solid front, it does support 3x 120mm or 2x 140mm fans in the front for intake through the meshed sides as well as up to a 280mm Radiator or 2x 120/140mm fans at the top. There’s also a pre-installed 120mm fan which can be swapped out if you’re looking to match the rest of your fans during a build. I/O on the top is simple and adequate with a Power Button, Restart Button, 2x USB 3.2 Gen 1 (formerly USB 3.0) and 1x 3.5mm Headset Jack (Audio+Mic). We would have loved to see USB 3.2 Gen 2 or USB-C support on this chassis but considering this is a budget product it ticks enough boxes for us by at least allowing easy access to some USB ports for removable storage.

While the chassis does support up to a mATX motherboard, we installed a Ryzen 3600X, 16GB Aorus DDR4 3600MHz RAM and a MSI B450I GAMING PLUS AC motherboard, due to ITX motherboards being surprisingly easier to get hold of than mATX motherboards at this stage. Thankfully unlike most ITX chassis, this small tower supports up to 166mm clearance for an Air-Cooler and as such we were easily able to install a CM Hyper 212 RGB. GPU clearance is also ample allowing up to 344mm long and up to 4 slot thick card to be installed, that means that even the 3 slot MSI RTX 3090 Suprim and 4-slot Aorus RTX 3090 Master could fit in this chassis – though we really wouldn’t recommend installing a 4-slot GPU due to there not being much airflow beneath it. In our example we installed a 2-slot MSI Radeon RX 5500 XT Gaming X which fit in as a comfortable physical medium.

Building in the chassis was honestly mostly effortless, it features cable channels and cut outs for all the basic areas you would expect, near the motherboard’s 8x CPU power as well as 24pin connections, near the GPU for PCIe power delivery as well as near the USB and Audio input alongside the top of the PSU shroud. While the chassis gets most of the basics right, one complaint we do have is that the thumb screws keeping the tempered glass side panel in place protrude quite far out which could be an issue if you’re planning to transport this chassis to a friends house or LAN, that is if the climate of the world ever changes.. I guess? Another note is that when screwing these in you’re likely to get finger smudges around the screws on the glass, so it would be great if Cooler Master could include a small micro-fiber cloth, else just allow for the side panel to be screwed in from the back like on their CM Silencio S600 that I use for my main gaming rig.

Considering that the MB400L retails for around R900 at local retailers it’s a perfect balance of price to performance and quality. It features most of the features that you’d want if you’re looking to build a small system with an ITX or mATX Motherboard, and regardless of what GPU you choose it will fit. Due to it even supporting large air coolers and most All-in-one Liquid Coolers up to 280mm we think that it deserves a recommendation for someone looking to save a bit on their new system, while still keeping a clean aesthetic that they can peer onto their components proudly through it’s tempered glass side panel. We need to be clear though that if you are planning to build something cutting edge like say a Ryzen 9 or i9 with a RTX 3090, you might want to look elsewhere as the front intakes are quite small and might hurt your performance due to cooling in the long run. This said, if you’re just looking to build a low to mid-range system for Gaming or Work, we give the MB400L a thumbs up.


Cooler Master MasterBox MB400L Chassis

A simple and clean chassis to fit most builds at a really affordable price