Sensor and Performance

The Redragon Cobra M711 FPS is equipped with the PixArt PMW3360. According to specifications, the 3360 is capable of up to 12,000 CPI, as well as a maximum tracking speed of 250 IPS, which equals 6.35 m/s. However, the Cobra M711 is capable of up to 24,000 CPI, which is achieved by using interpolation. Out of the box, five pre-defined CPI steps are available: 1000, 2000, 4000, 8000, and 12,000 CPI.

CPI Accuracy

"CPI" (short for counts per inch) describes the amount of counts registered by the mouse if it is moved exactly one 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 massive across the board, which is a subpar result. I've used adjusted steps of 400, 800, 1600, and 3000 to account for the measured deviation. I would've used 1500 instead of 1600, but the software, for whatever reason, did not allow that.

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.


First, I'm looking at two xCounts plots—generated at 1600 and 12,000 CPI—to quickly gauge whether there is any smoothing present, which would be indicated by any visible "kinks." As you can see, one major kink can be observed at 1600 CPI, whereas at 12,000 CPI, several kinks are visible. Let's proceed with the xSum tests for now.


Let us take a look at three additional xSum plots, generated at 1600, 3200, and 12,000 CPI. The line further to the left denotes the sensor with less motion delay. At 1600 CPI, motion delay is identical. Both 3200 CPI and 12,000 CPI show a motion delay differential of roughly 4 ms, which is expected as the PMW3360 has 32 frames of smoothing at and above 2100 CPI.

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 speed 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) show higher than average variance. Additionally, 1000 Hz suffers from dropped polls:


These dropped polls are the reason for the kink seen in the 1600 CPI xCount plot earlier.

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 CPI, and 3200 CPI, the latter of which already has smoothing applied, which takes care of the jitter. At 12,000 CPI, jitter is high but not excessive. Lastly, no sensor lens rattle can be observed.

Lift-off Distance

The Cobra M711 FPS offers no LOD adjustment whatsoever. This is unfortunate as the PMW3360 would be fully capable of it. At the default (and only) LOD level, the sensor does not track at a height of 1 DVD.

Click Latency

Most computer (and gaming) mice use mechanical switches for the buttons. Mechanical switches need debouncing in order to function as intended, which can add a delay, commonly referred to as click latency. The Redragon Cobra M711 FPS uses optical switches for the main buttons instead. Optical switches do not require any debouncing, hence no debounce delay is added. Unfortunately, this also means I'm unable to conduct my usual click latency testing. Using the less accurate and reliable "bump test," I'm able to measure results that indicate a click latency that is between 6–8 ms higher than that of the SteelSeries Ikari, which acts as the baseline (+0.0 ms).