Software

Much like most other recent Cooler Master releases, the MM731 is compatible with MasterPlus+, which is also referred to as MasterPlus, but not to be confused with MasterPlus, which is older and incompatible with the MM731. There are separate pages for wireless options, buttons, performance, lighting, macros, and profiles. Wireless options include Sleep Mode, which determines after how many minutes of idling the mouse will enter sleep mode. Low Power Mode defines at which battery percentage Low Power Mode is entered, though no indication is given on what said mode even does. From what I can tell, it merely disables illumination. All buttons except the left main button can be rebound, either to mouse, keyboard, macro, media, or OS functions. Additionally, Mouse Combo allows one to assign further functions accessible upon pressing a dedicated shift button. CPI adjustment is possible for up to seven levels and a range from 100 to 38,000 (interpolated past 19,000), along with the option to adjust x and y-axis values separately. Curiously, only multiples of 100 are available despite the 3370 natively supporting increments of 50 up to 10,000 CPI. Further settings include polling-rate adjustment (125, 250, 500, or 1000 Hz), angle snapping (on/off), and lift-off distance (low/high). Finally, as of the most recent update, button response time can be adjusted from 1 to 6 ms.

All settings are updated live and saved to the on-board memory, so the software does not need to be running (or be installed) all the time. On my system, the software has a RAM footprint of around 400 MB on average when running in the foreground, which doesn't change when minimized to the system tray. For whatever reason, RAM usage is wildly inconsistent. Most of the time, it was sitting at around 400 MB, but sometimes shot up to 500 MB and more. I'm unsure about what could be causing this behavior. Upon exiting the application, two processes with a RAM footprint of 5 MB keep running.

Lighting

The MM731 has but a single physical zone for RGB lighting, which is the logo at the back. A total of three pre-defined lighting effects are available in the software: Static, Breathing, and Cycle. For most effects, it is possible to set custom colors and adjust brightness as well as transition speed. Of course, disabling the lighting altogether is also possible.

Color accuracy and vibrancy are excellent throughout. Here's a short demonstration video in which I go through the Cycle and Breathing lighting effects:

Battery Life

According to Cooler Master, the MM731 has a battery life of 190 hours in Bluetooth and up to 72 hours if used in 2.4 GHz mode without illumination. MasterPlus+ includes a battery level indicator, though it lacks any kind of differentiation, be it bars or a percentage that would allow one to gauge anything. Eyeballing the battery indicator, I'd estimate the indicator to sit at roughly 80% after 12 hours of continuous use with RGB lighting enabled, which, using some crude arithmetic, may indeed roughly match the 72 hours cited by Cooler Master. In any case, that value is at least within the realm of possibility. For what it's worth, it seems curious that there is a percentage-based slider Low Power Mode works off, yet no percentage-based battery indicator.

Using the included USB Type-A to Type-C charging cable, I've measured the charging speed of the MM731 during the constant current (bulk) stage to be around 0.252 A. The battery has a capacity of 500 mAh.