Another case review: Coolermaster Masterbox Q300L


[H]F Junkie
Jun 12, 2012
Another day another case review, because why the hell not. But first thing's first, a little shameless self-promotion:
My previous case 'reviews'
Silverstone Fortress FT03
Shuttle SX79R5
Phanteks Enthoo Pro M
Coolermaster HAF 935
Silverstone Raven RV03

And now on to the current subject the Coolermaster Masterbox Q300L microATX Tower / Desktop case.

Link to manufacturer page

The reason I ordered this case was to upgrade my Shuttle barebone to a larger case for two particular reasons: To get rid of the loud PSU it came with, and to be able to use the second PCIE x16 slot on the board, because I couldn't fit a 2 expansion slot video card into the outer slot in the original case.

It might not be apparent on photo, but the box is huge for a microATX case.

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Without packaging.

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Yes it's ugly, because the cover is missing from the front, it actually comes with both covers fitted to the top. And they spared a few cents on packaging because the bottom one is not packaged just the one on top of it.

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The screws on the right panel double as stands so the case can be used both vertically and horizontally.

All the stuff removed.

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Continued in the next post.


[H]F Junkie
Jun 12, 2012
The PSU is attached to a bracket, that you first have to unscrew then attach to the PSU, then re-attach to the case:

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As it turns out the shuttle MB does not have it's screwholes at standard miniTX or microATX spacing, so I put electrical tape on the standoffs that does not line up properly with a hole:

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The expansion slots work in very stupid way on this case. In order to remove one card, you have to remove all, because the screws go trough a piece of metal that covers all the expansion slots.

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The only factory 3.5" expansion slot is under the MB tray as you can see in the above image. Not the greatest space for a HDD, as the bottom / right panel has no ventilation holes at all. But I want to fit 4 drives so I need to use it whether I like it or not. Also there is plenty of room in the same compartment for hiding cables.

Everything fitted:

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Yes that is a Noctue NH-D15. It just fits without touching the top panel. (Which is not actual tempered glass but plastic)

As this is a HTPC / server I'm not going to install any additional fans apart from the one in the back of the case.I'm not using the fan that came with the case as it was a low quality sleeve bearing fan. Replaced it with a CM Jetflo. And attached it to the CPU fan header.
Note: The factory noctua fans would not fit in this case anyway. You'd probably have to go one size smaller with the fans.

I've attached a 3x3.5" drive bay to the front of the case for the other 3 drives I had. The screws are completely hidden by the magnetic mesh.
Frankly I don't know why is that space left unused from the factory. I know it's the age of the SSD, but people still use spinners for storage right?

With the top cover on. And on the right you can see why I choose this case, it fits exactly into the space I had.

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Yes it's a blurry mess and I'm too lazy to take another picture.

Overall I really like the look of the case, but it is of typical Coolermaster quality (meaning barely fitting threads and impossible to use without a tool thumbscrews)

  • Exactly the size I needed
  • It fits a full tower cpu cooler.
  • all panels have dust filter meshes except rear.
  • It looks really nice.
  • Can be used as either a tower or desktop case.
  • The controls can be moved to another side of the case if someone needs that.
  • Plenty of room for hiding cables.

  • Just a single 3.5" expansion slot from factory.
  • The location of the 3.5" slot is not great.
  • A bit of a hassle to install the PSU
  • You need to remove all the expansion slot screws to remove just one of the cards.
  • Threads are a tight fit, thumbscrews are not really usable without a screwdriver
  • The paint comes off immediately from the screws / panels as soon as you insert a screw / screwdriver.


Styling: 9/10
Build Quality: 5/10
Practicality 3/10 (would give it a 6 if it had the 4x 3.5" slots from factory)

Final verdict: Would recommend if you don't need more 3.5" slots, or willing to do something similar to me.
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