CoolerMaster MasterBox Lite 3.1


I have a special treat for you today because I’m reviewing a case where there is very little information about around the internet. We will be looking at a very budget yet classy looking case from CoolerMaster. The Masterbox series of cases are meant to be affordable without skimping on design quality. The MasterBox Lite 3.1 is no exception and has some interesting features that make it stand out for an inexpensive case. Let’s dive deeper into what makes the Lite 3.1 so affordable yet sport an all see through design with modular components.

This review is a little non-traditional because I don’t have any specifications from CoolerMaster and I have no information about release dates. I will do my best to compare this to the MasterBox Lite 5 because it is basically the same except the 3.1 is for mATX sized motherboards.

Specifications from inspecting the case:

  • HDD Mount for 3.5″ and 2.5″ drives, 2.5″ SSD mount on top of HDD drive cage ( The cage can hold two drives each)
  • NO Internal DVD Drive mounting
  • Front Panel: Reset, 3.5 mm Mic and headphone in, Power button, USB 3.0 and 2.0 port, HDD LED activity light
  • Steel, Plastic, and clear Acrylic on front and side panel has full view side panel for a premium look
  • mATX motherboard dimensions
  • Front x2 120mm fans or up to 240mm radiator support
  • Rear 120mm (MasterFan Pro included)
  • Graphics card length: 345mm Max
  • CPU cooler height 157mm
  • Custom modular plates can be swapped out with different colors on front panel (Includes White, Red, and Black)
  • PSU Dust cover for bottom mounted PSUs

Will update officially when specs are available*

Why Choose MasterBox?


MasterBox is a series of cases designed for customization at an affordable price. The new Lite 5 & 3.1 offer a sleek DarkMirror front panel with three custom colored strips for easy configuration. The MasterBox Lite 5 offers a PSU covered shroud but the Lite 3.1 does not and the major difference is mATX for the 3.1 and ATX for the 5. The best highlight of each case is the edge to edge transparent acrylic side panel which gives a premium look but at an affordable price tag. Both cases offer a direct airflow design from front to back and can accommodate CoolerMaster’s new RGB fans for a displaying their colorful design and effects. These cases also support CoolerMaster’s 3D Printing so you can express and design your own case covers.


IMG_1982  IMG_1983

Don’t let the box fool you this was for some reason shipped to me in the MasterBox Lite 3 box, which leads believe I may not even have a final product here. Let’s dig deeper and see what is offered for this budget-oriented case. The case was shipped using styrofoam to protect it during shipment.

IMG_2003  IMG_2006

The accessories included are as follows:

  • MasterBox Lite 3.1
  • Screw set / Zip ties
  • Swappable colored panels for front cover
  • Warranty and documentation
  • Removable PSU dust cover

Design & Build Process

IMG_2076  IMG_2001 (1)

The design of this case is well thought out and provides a stylish look for all your components. One of the key parts of this case is the modular brackets for the front panel. I chose black because it fit the best with my current color scheme. If you interested you can also download templates for creating your own brackets here.

The Lite 3.1 provides enough space for an mATX case and also just enough room for some cable management behind the motherboard tray. It’s a little bit of a tight fit but is definitely manageable. You can fit ATX, mATX, and Mini-ITX in the Lite 5, but the Lite 3.1 fits mATX and Mini-ITX.

IMG_1992  IMG_1997

The front I/O consists of your basic functionality like USB 3.0 & 2.0 ports and the bottom supports a rear sliding PSU dust filter. One of the disadvantages of rear sliding dust filters is that you have to have access to the back of the case to get to the cover. It’s much easier if you have your case against a wall to slide a filter from the front than it is from the rear.

IMG_2016  IMG_2017

The front of the case looks good having the DarkMiror finish which is nice for showing up RGB or color LED fans, but not so great for airflow. The front of this case does not have sufficient airflow using the direct airflow design. You can see in the above picture how restricted airflow is and this is not good for radiators or regular mounted fans. The front supports 2x 120mm fans or a 240mm radiator. I did install the MasterLiquid 240 but having the restricted airflow and honeycomb design causes a subtle annoying whistling noise. If you are installing a CPU air cooler the supported size is 157mm in height.

Later you will see, but temperatures were okay and within reason, it’s just the low airflow that doesn’t have enough ventilation that causes the trapped air to pull through the small opening of the included modular vents.


Removing the vents is really easy and only requires a few screws and mesh be removed before applying the other ones you want or your 3D printed design. You can swap out the top and bottom independently if you want to mix and match colors.


The rear of the case include one MasterFan Pro for exhaust and is pre-installed. You also get 4 expansion slots being an mATX size case and most likely you will be installing a dedicated GPU, so that leaves only two more for use.

You can install a GPU up to 345mm in length which is ideal for dual fan cards and keeps your options open. The Lite 3.1 also support SLI configurations and dual slot cards. mATX is a good balance between keeping your PC footprint smaller while still maintaining an enthusiasts approach and upgradability.


The hard drive cage supports two drives and has a 2.5″ mount on top of the cage as well. Ideally, you could install either two 2.5″ or 3.5″ and one 2.5″ on top of the cage. The cage is removable which helps when managing your cables.

IMG_2025 (13)  IMG_2042

One of the things I did like about the Lite 3.1 is that it does have some room behind the motherboard tray compared to a lot of mATX cases that don’t. Even the Lite 3 Doesn’t offer very much room for cable management. The Lite 3.1 doesn’t have a ton of clearance but it does offer some, and I would much rather a little than none at all. When you have such a compact case like this it’s hard to find room to manage cables due to size restrictions. I can say that I did have enough room for my AIO 240 from CoolerMaster and tucking away all the cables neatly behind the motherboard tray. They did have cut outs along the right side for the 24 pin, SATA, and GPU power connectors.

Another drawback I found here that was disappointing was the lack of an 8-pin CPU motherboard cut out. In 2017, this is sort of confusing why this was missing. I had to route the 8-Pin motherboard CPU power connector behind the motherboard where there was barely enough space. This did put a bit of pressure on my motherboard, and I wasn’t worried about any damage but I don’t like anything pressing against my components.


Building inside the Lite 3.1 is surprisingly easy and offers a nice compact design for a small footprint. The major drawback I saw here while building, was the restricted direct airflow design. This could cause major heat issues with SLI and CPU temps at lower fan speeds. When you run the fans at higher RPM you get a whistling noise due to the air being pulled in through the small vent slots.

The edge to edge design of the acrylic side panel gives the case a tempered glass look without the major price tag. It does look really nice and does a great job at showing off your components inside. This is a smart move on CoolerMasters part and we don’t see a ton of case manufacturers that have a design like this. My favorite slogan they have for the MasterBox Series is “BECAUSE YOUR CASE DOESN’T HAVE TO BE BORING”.



My test bench is as follows:

  • ViewSonic XG2703-GS Monitor
  • Motherboard- ASRock z270m Extreme 4
  • CPU: Intel Core I7 6700K
  • Network Card- Netgear AC 1200 USB
  • Cooler- Cooler Master Master Liquid 240
  • Memory- Corsair LPX DDR4 3000 MHz
  • Video Card: Nvidia GTX 1060
  • Storage- MyDigital SSD BPX 480 GB NVMe x2 RAID 0 Drives (Boot) / BP5e 960GB / Other test drives vary
  • Power Supply- Corsair RM650X
  • OS: Windows 10 x64 Pro
  • Mouse- Logitech G403 Wireless Gaming Mouse
  • Keyboard- Logitech G413
  • Headphones- Logitech G533 7.1 Surround Sound Wireless Headset

For testing, I overclocked my CPU to 4.5 GHz and will test noise and cooling. I used Prime 95 and Aida64 Extreme to test load performance. The load performance will consist of max RPM for fans and temperatures recorded. You can use software or your BIOS to control fan curves or PWM fan speeds.  I suspect the 3.1 to have a higher noise level due to the restricted airflow and whistling noise at higher RPMs.

I don’t have very many cases yet to test this against because the Lite 3 is designed differently and the Lite 5 has the same design but is much more open and may have different airflow. The MasterBox 5 supports 3x fans instead of the 2x with the 3.1. I haven’t gotten a MasterBox Lite 5 from CoolerMaster yet to even test against.

I record temperatures using Real Temp and an IRT207 infrared thermometer for case temps, as well as spot checking with my FLIRONE.

The FLIRONE! is fantastic because it will allow tech enthusiasts and reviewers to show visual results for thermal testing. It is a next generation thermal camera that works with iOS and Android devices. If you want to buy one look here.


For noise testing, I used a high gain microphone. I want to explain a few things about noise testing, and this unit in particular.

First: Testing noise levels can be difficult. First, don’t expect the same levels even with similar hardware. There are too many differences and variables that go into sound testing. You have to account for background noise and other sounds in the environment.

Second: I am one reviewer, and am not a professional sound studio. I am not testing these items in perfect conditions. I do not have an anechoic sound chamber in my test studio.


There is some important information that can be taken from the numbers above. First, the High setting for the front intake is going to be louder and also contribute to even the rear levels because it adds a whistling noise from the restricted airflow. The lower setting even though the whistling noise goes away I still have other system noises in the background contributing to the overall noise level, and in such a small case the testing points are not too far from each other. This should explain the close gaps, and when I was testing right in front of the intake why it was a little higher due to the added noise.


The temperatures were spot on with what I would expect for the AIO and direct airflow design. While the whistling noise is a bit annoying, it does indicate air is being pulled through correctly even though its restricted. I tested temps on load which was a stress test during Adia 64, Normal Gaming load, and idle temperatures. I used my FLIRONE for spot checking and referencing with an IRT207 infrared thermometer for case temps. I also used core temp and Adia 64 to make sure the temperatures were within reason of error.


The FLIRONE image does a great job showing real world results for the Lite 3.1. You can see purple being the coolest spots right in front of the rear fan. This shows that the direct airflow design is doing a good job eliminating head from the crucial spots in the case. The rear fan is set as exhaust and also note the AIO water block is also doing a great job keeping the CPU cool. The VRM and heat around the area are what is hottest and the rear fan is pulling the air out fo the case, you can actually see some of the heat on the fan which is represented by the orange spot where the bearings are. The temp listed above from the FLIRONE was actually during normal gaming loads and is a bit cooler because I measured closer to the fan.


cases dark mirror.JPG

The MasterBox Lite 3.1 was a pleasure to work in. Most mATX cases don’t provide a lot of room to work in with cable management, but this is a step in the right direction. My biggest issue is with the modular plates and restricted airflow. What CoolerMaster could do to improve this would to have vents along the angled side of the front DarkMirror panel. This would allow more air to enter hopefully elimination that whistle noise.

I haven’t gotten to the entire best part of this case yet and that is the price. This case is only $39.99 for all the features it supports. It’s extremely hard to argue the performance you get for a price like that. The only thing is I am unsure when this will be released, and it should be soon. Once I have official specifications, and product links I will be updating this review. In the meantime, you can check out both the MasterBox Lite 3 here and the MaterBox Lite 5 here.


CoolerMaster MasterBox Lite 3.1

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