Sensor and Performance

The Mountain Makalu 67 is equipped with the PixArt PAW3370 sensor. According to specifications, the 3370 is capable of up to 19,000 CPI, as well as a maximum tracking speed of 400 IPS, which equals 10.16 m/s. Out of the box, five pre-defined CPI steps are available: 400, 800, 1200, 2000, and 19,000.

All testing was done on the latest firmware. As such, results obtained on earlier firmware versions may differ from those presented hereafter.

CPI Accuracy

"CPI" (short for counts per inch) describes the amount of counts registered by the mouse if it is moved exactly an inch. There are several factors (firmware, mounting height of the sensor not meeting specifications, mouse feet thickness, mousing surface, among others) which may contribute to nominal CPI not matching actual CPI. It is impossible to always achieve a perfect match, but ideally, nominal and actual CPI should differ as little as possible. In this test, I'm determining whether this is the case or not. However, please keep in mind that said variance will still vary from unit to unit, so your mileage may vary.


I've restricted my testing to the four most common CPI steps, which are 400, 800, 1600, and 3200. As you can see, deviation is low and exclusively negative. A very good result overall. In order to account for the measured deviation, adjusted steps of 400, 800, 1600, and 3250 CPI have been used for testing.

Motion Delay

"Motion delay" encompasses all kinds of sensor lag. Any further sources of input delay will not be recorded in this test. The main thing I'll be looking for in this test is sensor smoothing, which describes an averaging of motion data across several capture frames in order to reduce jitter at higher CPI values, increasing motion delay along with it. The goal here is to have as little smoothing as possible. As there is no way to accurately measure motion delay absolutely, it can only be done by comparison with a control subject that has been determined to have the lowest possible motion delay. In this case the control subject is a G403, whose 3366 has no visible smoothing across the entire CPI range. Note that the G403 is moved first and thus receives a slight head start.


The 3370 has a variable frame rate, which has no frame rate transitions show up in xCount plots. As such, we'll have to take a look at xSum plots to determine motion delay. What we can see, however, is how little difference there is between the two plots despite the huge difference in effective CPI.


In order to determine motion delay, I'm looking at xSum plots generated at 1600, 3200, and 19,000 CPI. The line further to the left denotes the sensor with less motion delay. As you can see, the motion delay differential at the tested steps is within margin of error. Accordingly, we can conclude that the 3370 in the Makalu 67 has no smoothing across its entire CPI range.

Speed-related Accuracy Variance (SRAV)

What people typically mean when they talk about "acceleration" is speed-related accuracy variance (or short SRAV). It's not about the mouse having a set amount of inherent positive or negative acceleration, but about the cursor not traveling the same distance if the mouse is moved the same physical distance at different speeds. The easiest way to test this is by comparison with a control subject that is known to have very low SRAV, which in this case is the G403. As you can see from the plot, no displacement between the two cursor paths can be observed, which confirms that SRAV is very low.

Perfect Control Speed

Perfect Control Speed (or PCS for short) is the maximum speed up to which the mouse and its sensor can be moved without the sensor malfunctioning in any way. I've only managed to hit a measly 4.0 m/s (which is within the proclaimed PCS range), at which no sign of the sensor malfunctioning can be observed.

Polling Rate Stability

All four available polling rates (125 Hz, 250 Hz, 500 Hz, and 1000 Hz) look nice and stable. Polling stability is unaffected by all but the "Color Wave" RGB setting, which shows occasional drops to 500 Hz:

Paint Test

This test is used to indicate any potential issues with angle snapping (non-native straightening of linear motion) and jitter, along with any sensor lens rattle. As you can see, no issues with angle snapping can be observed. No jitter is visible at 400, 1600, and 3200 CPI. 19,000 CPI shows major jitter, but considering the lack of smoothing, it's quite reasonable. Lastly, there is no sensor lens movement.

Lift-off Distance

The Makalu 67 offers two pre-defined LOD levels to choose from. At the default "Low" setting, the sensor does not track at a height of 1 DVD (<1.2 mm). At the "High" setting, the sensor does track at a height of 1 DVD, but not at a height of 2 DVDs (1.2<x<2.4 mm; x=LOD height). Keep in mind that LOD may vary slightly depending on the mousing surface (pad) it is being used on.

Click Latency

Since mechanical switches are being used for the buttons in most computer mice, debouncing is required in order to avoid unintended double clicks. Debouncing typically adds a delay (along with any potential processing delay), which shall be referred to as click latency. As there is no way to measure said delay directly, it has to be done by comparing it to a control subject, which in this case is the Logitech G203. Using the 2 ms Button Response Time option within the software, click latency has been measured to be roughly +5.0 ms when compared to the SteelSeries Ikari, which is considered as the baseline with 0 ms. Please keep in mind that the measured value is not the absolute click latency. Comparison data comes from this thread as well as my own testing, using qsxcv's program.