Sensor and Performance

The Strix Impact II is equipped with the PixArt PAW3327. According to specifications, the 3327 is capable of up to 6200 CPI, as well as a maximum tracking speed of 220 IPS, which equals 5.59 m/s. Out of the box, four pre-defined CPI steps are available: 400, 800, 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 as well.


I've restricted my testing to the four most common CPI steps, which are 400, 800, 1600, and 3200. As you can see, the deviation is something else. The absolute deviation at the lower steps in particular is massive, yet the relative deviation gets progressively smaller the higher the CPI is. All in all, a bad result. For my testing, I've used corrected steps of 300, 700, 1500, and 3200 CPI in order to account for the measured deviation.

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.


The 3327 doesn't have fixed framerate levels, which has no framerate transitions show up in these two xCount graphs. However, we can see that the tracking is quite clean, with very little jitter.


Here, I'm looking at xSum plots generated at 1600, 5000, and 5100 CPI. The line further to the left denotes the sensor with less motion delay. At 1600 CPI, motion delay is identical; at 5000 CPI, motion delay is still identical; and at 5100 CPI, motion delay is roughly 2 ms. It stays at 2 ms all the way up to 6200 CPI. To sum it up, smoothing kicks in very late, and only to a very moderate degree even then.

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

250 Hz shows slightly above average variance, but everything else (125 Hz, 500 Hz, and 1000 Hz) looks nice and stable. 500 Hz is the default setting.

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. I'm testing 1600 CPI as a general use baseline; 5000 CPI as the last non-smoothed step; 5100 CPI as the first smoothed step; and 6200 CPI as the highest CPI step. As you can see, no issues with angle snapping can be observed at any CPI step. No jitter is visible at 1600 CPI, but there is some jitter at 5000 CPI, which barely decreases at 5100 CPI. 6200 CPI doesn't look much different, so overall jitter is under control throughout the entire CPI range. Lastly, there is no sensor lens rattle.

Lift-off Distance

The Strix Impact II does not support adjusting LOD. At the only available (default) setting, the sensor tracks at a height of 1 DVD, but not at a height of 2 DVDs. However, 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. Click latency has been measured to be roughly +11.9 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.