Cooler Master MasterBox NR400 Review

March 19, 2019 | 11:45

Tags: #case #chassis #sff #small-form-factor #tempered-glass #tower-case #tower-chassis

Companies: #cooler-master

Manufacturer: Cooler Master

UK price (as reviewed): MSRP £59.99 (inc. VAT)

US price (as reviewed): MSRP TBC

In the sea of RGB and tempered glass cases with inflated price tags it can be difficult to remember that humbler cases still exist. One such case is the new Cooler Master MasterBox NR400, which comes in at just £60 and is a micro-ATX tower chassis with high-airflow aspirations. It’s available both with and without optical drive support, and a bigger ATX sibling, the NR600, will also launch today for £70.

Made mostly of steel but coming with a tempered glass side panel and plastic front panel, the MasterBox NR400 has build quality that befits its price. By this we mean that the steel is thinner than you’d get on more premium cases, and the sub-6kg weight is testament to this (as well as its size) as well. Thankfully Cooler Master hasn’t gone too far south here, as panel alignment and structural integrity are fine.

The front panel is a strong indication that Cooler Master is taking its ‘high-airflow’ marketing seriously, as it is fully ventilated from top to bottom thanks to a single layer of mesh that’s fine enough to double up as a dust filter. It pulls off quickly and easily with a tug from beneath, so you can clean it and replace it without fuss. This will also allow you to access the fan mounts and optical drive mount, the cover for which simply pops out of the main front panel.

Up front you have a single 120mm intake fan, and the position chosen is optimal for GPU cooling. It’s complemented by a rear 120mm exhaust, so airflow should be nicely balanced. There’s also room for dual 140mm or 120mm fans in the roof, which is again heavily ventilated, and up to two 140mm or three 120mm fans in the front. Note that on our ODD version of the chassis, default fan support is one in the roof and two in the front, but removing the optical drive tray will bring fan support up to the level of the non-ODD version if you later decide to expand cooling and do away with the ODD.

We can overlook the absence of USB 3.1 Type-C on the front I/O on a £60 chassis, with Cooler Master instead opting for power and reset buttons plus dual USB 3.0 Type-A ports and a single four-pole (TRRS) audio jack with stereo headphone/microphone functions combined.

Initially we were perplexed to see the roof devoid of a dust filter, but we found it stuck to the inside of the right steel side panel. It’s flexible and magnetic and slots neatly into place, so thumbs up there, but the thin filter on the bottom guarding the PSU is too flimsy even for this price level, and it’s a pain to work with as well. One small saving grace on the underside is that Cooler Master is using rubber-tipped feet rather than the foam (or nothing) that’s often found on cheaper chassis.


  • Dimensions (mm) 210 x 411 x 411 (W x D x H)
  • Material Steel, plastic, tempered glass
  • Available colours Black
  • Weight 5.72kg
  • Front panel Power, reset 2 x USB 3.0, 1 x 3.5mm jack (headphone + microphone)
  • Drive bays 4 x 3.5", 4 x 2.5"
  • Form factor(s) Micro-ATX, mini-ITX
  • Cooling 2 x 140mm/120mm front fan mounts  or 3 x 120mm with ODD removed (1 x 120mm fan included), 1 x 120mm rear fan mount (1 x 120mm rear fan included), 1 x 140mm/120mm roof fan mount or 2 x 140mm/120mm with ODD removed (fans not included)
  • CPU cooler clearance 166mm
  • Maximum graphics card length 346mm
  • Extras Removable dust filters, three-way 12V Molex fan splitter

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