Sensor and Performance

The Endgame Gear XM1r is equipped with the PixArt PAW3370. 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, four pre-defined CPI steps are available: 400, 800, 1600, and 3200.

All testing was done on the latest firmware (1.8.120). As such, results obtained on earlier firmware versions may differ from those presented hereafter.

CPI Accuracy

"CPI" (short for counts per inch) describes the number 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 differ 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 minimal, which is an excellent result. To account for the measured deviation, adjusted steps of 400, 800, 1600, and 3150 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.


First, I'm looking at two xCounts plots—generated at 1600 and 19,000 CPI—to quickly gauge whether there is any smoothing, which would be indicated by any visible "kinks." As you can see, no kinks are in sight. Thus, we can conclude that the 3370 implemented in the XM1r has no visible smoothing across the entire CPI range. We also see rather low SPI timing variance, which results in fairly tight count distribution.


In order to determine motion delay, I'm looking at xSum plots generated at 1600 and 19,000 CPI. The line further to the left denotes the sensor with less motion delay. Neither 1600 nor 19,000 CPI show any difference in motion delay, which merely confirms the results seen above. I wasn't able to get the Ripple Control setting working in the software, which is supposed to lessen jitter at higher CPI steps (i.e., smoothing) at the cost of increased motion delay.

Speed-related Accuracy Variance (SRAV)

What people typically mean when they talk about "acceleration" is speed-related accuracy variance (or SRAV for short). 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 4.5 m/s, which is within the proclaimed PCS range and shows no sign of the sensor malfunctioning.

Polling Rate Stability

All three polling rates (125/500/1000 Hz) look nice and stable.

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 1600 or 3200 CPI. Minor jitter is visible at 10,100 CPI, which is further amplified at 19,000 CPI, although it still remains surprisingly well-controlled. Lastly, no sensor lens movement can be observed.

Lift-off Distance

The XM1r allows choosing between two pre-defined LOD levels. At the 1 mm setting, the sensor does not track at a height of 1 DVD (<1.2 mm). Using the 2 mm setting, the sensor does track at a height of 1 DVD, but not at a height of 2 DVDs (1.2 mm<x<2.4 mm, with x being LOD height). Keep in mind that LOD may vary slightly depending on the mousing surface (pad) it is being used on.

Click Latency

Like most mice, the XM1r uses mechanical switches for its buttons, but it does not debounce them in the traditional way. Instead, Endgame Gear employs a method called "Analog Switch Technology," which basically eliminates all delay that would be introduced by traditional debouncing while nullifying the possibility of double-clicking due to insufficiently high debounce time values. For further details on this analog switch technology, please refer to the patent here. The absence of traditional debouncing also means I cannot use my usual method for determining click latency. As such, the less reliable bump test will have to suffice. Testing against the Logitech G203, my measurements suggest a click latency roughly equal to the SteelSeries Ikari, which is considered as the baseline with 0 ms.