Sensor and Performance

The ROCCAT Kain 100 is equipped with the PixArt PMW3331. According to specifications, the 3331 is capable of up to 8500 CPI, as well as a maximum tracking speed of 300 IPS, which equals 7.62 m/s. Out of the box, five pre-defined CPI steps are available: 400, 800, 1200, 1600, and 3200.

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 decently low, but fairly inconsistent, which is a good result.

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 xCount plots in order to determine whether there is any smoothing present, which would be indicated by any visible "kinks," and if there is, at which threshold it kicks in. As you can see, no such kinks can be observed at 4900 CPI, whereas at 5000 CPI, it's plainly visible. We can therefore conclude that the smoothing kicks in at and above 5000 CPI. Furthermore, we can also conclude that the 3331 does not have a fully variable framerate, but several fixed framerate modes. Additionally, there's an interesting detail I noticed with the software: although the CPI slider defaults to increments of 100, increments of 50 can be entered manually. They aren't correctly applied, though, and default to a (much lower) fixed CPI value. ROCCAT is currently looking into whether that's a bug. The highest CPI step without smoothing is therefore 4900. Lastly, SPI timing has fairly little jitter, which is a good thing.


In order to verify the results from the xCount plots above, I'm looking at xSum plots generated at 4900, 5000, and 8500 CPI. The line further to the left denotes the sensor with less motion delay. At 4900 CPI, motion delay is identical; at 5000 CPI, motion delay is roughly 2 ms; and at 8500 CPI, motion delay is still 2 ms. To sum it up, smoothing is very minor and only kicks in at 5000 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 m/s (which is within the proclaimed PCS range), at which speed no sign of the sensor malfunctioning can be observed.

Polling Rate Stability

Variation at 250 Hz is a bit higher than I'd want it to be, but otherwise, everything looks 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. This time around, I'm testing four CPI values: 1600 CPI as a general use baseline; 4900 CPI as the highest CPI step without any smoothing; 5000 CPI as the first CPI step with smoothing; and 8500 CPI as the highest CPI step with smoothing. As you can see, no issues with angle snapping can be observed at any of the tested CPI steps. 1600 CPI already shows minor jitter. At 4900 CPI, jitter is major, and only moderately lessened at 5000 CPI, where minor smoothing is first applied. 8500 CPI then shows very high jitter. For me personally, the amount of jitter at any CPI step over 3500 CPI is a bit too much. Furthermore, minor sensor lens rattle can be observed.

Lift-off Distance

The Kain 100 does not support adjusting LOD. The only available (default) setting is moderately high as it does track at a height of 1 DVD, but not at a height of 2 DVDs. It should be kept 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.

The ROCCAT Kain 100 features a rather interesting and unusual function in the software called "Zero Debounce." The naming scheme is highly descriptive as it does exactly what it sounds like. With Zero Debounce set to off the usual debouncing is performed, which introduces a delay but prevents slam clicks from happening. With it enabled, no debounce delay is applied, reducing click latency accordingly, but introducing the possibility of slam clicks. With Zero Debounce disabled, click latency has been measured to be roughly +7.9 ms when compared to the SteelSeries Ikari, which is considered as the baseline with 0 ms. With Zero Debounce enabled, click latency has been measured to be roughly +2.9 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.