Cooler Master MasterBox Q300L and Q300P are tidy and affordable

We got our first look at Cooler Master's MicroATX Q300 line of cases back at Computex last June, and we saw two of the three prototypes again at CES in January. Those same two models, the MasterBox Q300L and MasterBox Q300P, are now ready to ship to those builers that don't need a full ATX motherboard's expandability but aren't ready for the human oragami needed for most Mini-ITX builds.

The MasterBox Q300L is a rather understated case with a dark color scheme, a full-size transparent window, and an optional handle. The MasterBox Q300P uses the same core chassis but adds RGB LED illumination, a transparent front panel, and four removeable protrusions that can function as grab handles or elevating legs. The side-mounted I/O panel on the cases can be moved into any of six different locations depending on where the case is positioned relative to the user.

Cooler Master MasterBox Q300L

Both chassis fit Mini-ITX or microATX motherboards. Tower coolers up to 6.2" (15.7 cm) tall can sit astride the processor without hitting the side panel. Graphics cards as long as 14.2" (36 cm) can fit, as can ATX power supplies up to 6.3" (16 cm) in length. The Q300-series cases have room for two 2.5" storage devices and a single 3.5" drive. Luddites clinging to their optical media will need to invest in an external reader of some kind. Cooler Master says the Q300 siblings have 1.1" (2.8 cm) of room behind the back of the motherboard tray and the steel right side panel, which shoud aid in getting the feng shui of the main compartment just right.

Cooler Master MasterBox Q300P

The cases' shared core chassis means they both handle the same cooling gear. Builders can stuff in a 240-mm radiator behind the front panel and a 120-mm liquid-to-air cooler in the back panel. A pair of 120-mm fans fit in the top panel and another 120-mm rotating air mover mounts into the bottom side, just in front of the power supply. Cooler Master says the patterned plastic front and top panels of the Q300L aren't just decorative and act as removeable dust filters, too.

Cooler Master MasterBox Q300L with carrying handle

The more compact Q300L measures 15.2" deep, 9.1" wide, and 14.9" tall (39 cm x 23 cm x 38 cm). The Q300P has the same width, but the body mods push the depth and height to 17.7" (45 cm). The previously-referenced repositionable I/O panel has power and reset buttons, plus two USB 3.1 Gen 1 ports and audio jacks for a headset. The Q300L has a single 120-mm fan pre-installed in the back panel.

Cooler Master's MasterBox Q300L is available now from Newegg for an affordable $40. The more accessorized MasterBox Q300P is listed for $70 at the same e-tailer, though it's currently listed as out of stock. Some of the extra scratch for the Q300P goes to the addition of an RGB LED controller and a pair of factory-equipped color-changing fans in the front panel. As for the third prototype in the series, the company hasn't shown or talked about the MasterBox Q300T since Computex.

Comments closed
    • Chrispy_
    • 2 years ago

    Oooh, a new mATX case that’s actually not just a regurgitated ATX design with 2 or 3 expansion slots taken out.

    I’d be interested if they sold it without a heavy, pointless slab of tempered glass instead of a side panel – there’s obviously zero cable-management in a single-chamber box like that, so who the hell wants a tempered-glass view of the full cable-spaghetti in all its glory?!

      • Eastman
      • 2 years ago

      The transparent panel is actually of plastic and not tempered glass so the whole case is not heavy at all. I don’t think they would sell tempered glass at this price. You should check other articles, you’ll see you can wire the drives through the other side of the case. I think it’s a great little case at a very affordable price. I might just order one for a compact affordable mATX build.

    • LocalCitizen
    • 2 years ago

    i wish the case makers could design the cases just 1/4 inch taller so i can fit a 240/280 radiator on top to expel the hot air from cpu / gpu outwards.
    it doesn’t make sense to me to have the radiator on the front and blow hot air inside the case.

      • Waco
      • 2 years ago

      So run the fans to exhaust out the front. :shrug:

        • LocalCitizen
        • 2 years ago

        for the cases without top vents where would they draw cool air from? the back?

          • Waco
          • 2 years ago

          Rear, top, or bottom. Or feed from the front and not worry about the slightly higher case temps.

      • Shobai
      • 2 years ago

      I think it makes perfect sense; you don’t want to lower the efficiency of the radiator by having it pass pre-warmed air over its cooling array.

      I don’t care to see the entire surface of the motherboard – what a waste. With no tower heatsink on the CPU, I’d rather see that wasted volume taken up by returning the PSU to that area in order to leave the front and bottom case surfaces free for radiator installation.

        • LocalCitizen
        • 2 years ago

        but the radiator on top is not just blocking the motherboard. it is blocking the ram or vrm heatsink or the motherboard io. just read the newegg case comments. people had to resort to drilling holes at an offset to make things fit.

        these cases are just about perfect. all i’m asking is a fraction of an inch more clearance from the top of the motherboard. it will make many people happy.

          • Shobai
          • 2 years ago

          You commented ‘it doesn’t make sense’, and I replied to that specifically. You don’t appear to have taken that on board; your reply is neither here nor there.

      • Kraaketaer
      • 2 years ago

      “it doesn’t make sense to me to have the radiator on the front and blow hot air inside the case.”

      I disagree. As long as the liquid cooling system is sufficient to keep temperatures in check, the air exiting the radiatior won’t be all that hot. If you have an air cooled GPU it might cause it to not boost as high, but with a full custom loop or AIO-cooled GPU, this is not an issue. Nothing will come close to overheating. I cool my 1600X + Fury X with a loop consisting of a 240 and a 120mm rad, where the 240 is front intake and the 120 is currently my only exhaust. This works very, very well, even at low fan speeds, despite the PC routinely exceeding 400W draw from the wall while gaming. Nothing on the motherboard gets even close to uncomfortably warm, let alone overheating.

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