Sensor and Performance

The EVGA X17 is equipped with the PixArt PMW3389. According to specifications, the 3389 is capable of up to 16,000 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: 800, 1600, 3200, 6400, and 16,000, with the sniper button set to 400 CPI.

All testing was done on the latest firmware. As such, results obtained on earlier firmware versions may differ from those presented hereafter. Unless noted otherwise, I'll exclusively test the X17 at 1000 Hz on this page. This is done both to provide the full picture and establish a baseline for testing polling rates higher than 1000 Hz, which follows on the next page.

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 exclusively positive, very consistent, and decently low, which is a very good result overall. In order to account for the measured deviation, adjusted steps of 400, 800, 1550, and 3100 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 X17 is moved first and thus receives a slight head start.


First, I'm looking at two xCounts plots generated at 1600 and 3200 CPI. Typically, the 3200 CPI plot would show such "kinks" given the 3389 usually has 32 frames of smoothing at and above 1900 CPI, which is then doubled at 6000 CPI and 11,300 CPI. As you can see, this is the case here, although the kinks are just barely visible. This confirms that the 3389 in the X17 is performing as expected. We can also see fairly low SPI timing jitter.


In order to determine motion delay, I'm looking at xSum plots generated at 1600, 3200, and 16,000 CPI. The line further to the left denotes the sensor with less motion delay. As you can see, 1600 CPI effectively shows the X17 coming out slightly ahead of the G403, whereas 3200 CPI shows a motion delay differential of roughly 2 ms in favor of the G403 and 16,000 CPI a differential of roughly 10 ms. This is significantly less than one would expect from a 3389 with the standard SROM. I suspect this may be due to the sensor running at a higher (and possibly fixed) framerate than by default, which makes sense for polling rates higher than 1000 Hz, as there is more overlap between individual frames. Since smoothing is applied to a fixed number of frames, a higher framerate results in a lower absolute delay. On the other hand, it could also be explained by the number of frames of smoothing being lower, or the timing intervals between SPI and USB being smaller. In short, it's difficult to tell for sure.

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 4.0 m/s (which is within the proclaimed PCS range), at which no sign of the sensor malfunctioning can be observed.

Polling-rate Stability

Except for what is pictured below, all tested polling-rate settings (125 Hz, 250 Hz, 500 Hz, and 1000 Hz) look nice and stable:


Roughly every 3000 ms, a "burst" of off-period polls occurs. This is reproducible across all polling rates up until 2000 Hz and RGB lighting effects. Polling stability is unaffected by any RGB 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. As you can see, no issues with angle snapping can be observed. No jitter is visible at 1600 CPI and 3200, the latter of which already has the first level of smoothing applied. 16,000 has more smoothing and jitter, but compared to other 3389 implementations, the latter is surprisingly well-controlled. Lastly, there is no sensor lens movement.

Lift-off Distance

The X17 does not offer any pre-defined LOD levels to choose from right from the get-go. Instead, one has to perform a surface calibration first, which will lower the LOD beyond the default level. From there, one can choose between four different "preference" settings: office, universal gaming, FPS gaming, and custom. The latter allows one to choose from three non-discrete levels: High, Low, and Xtreme Low, for "LOD1" and "LOD2." LOD1 refers to the LOD sensor next to the main sensor, whereas LOD2 refers to the one in the front. Yet only LOD2 seems to have any effect, so I'm uncertain about the purpose of this distinction. Set to High, 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). Set to Low or Xtreme Low, the sensor does not track at a height of 1 DVD (<1.2 mm). 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. At a polling rate of 8000 Hz, click latency has been measured to be roughly +7.4 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.