Sensor and Performance

The Mad Catz R.A.T. Pro X3 Supreme 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, four pre-defined CPI steps are available: 800, 1600, 3200, and 16,000.

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 massive and exclusively positive. A poor result overall. In order to account for the measured deviation, adjusted and mostly accurate steps of 350, 700, 1400, and 2800 CPI have been used for testing. Please note that those measurement have been done using the ceramic feet installed by default. Using the PTFE feet, the deviation is even greater. Also note that testing has been performed at a polling rate of 1000 Hz. Using 2000 Hz or 3000 Hz, CPI ends up considerably lower, thus resulting in less deviation. It seems as though the steps were specifically tuned for polling rates higher than 1000 Hz. That said, I have no idea why the polling rate has an effect on actual CPI.

2000 and 3000 Hz USB Polling: Does It work?

Mad Catz promises a USB polling rate of 2000 Hz on the R.A.T. Pro X3 Supreme. Now, the question is: Does it work? The short answer is no. First of all, the R.A.T. Pro X3 Supreme is detected as a full-speed device, which already calls into question the ability to deliver actual 2000 Hz polling. Furthermore, bInterval is listed as "0x01," which indicates a polling interval of 1 ms (1000 Hz) instead of 0.5 ms (2000 Hz) or 0.33 ms (3000 Hz). Looking at the interval plots then removes any remaining doubt:


As you can see, the mouse simply sends three identical updates in every packet. Doing so serves no purpose other than faking readings. In actuality, no additional data is submitted, thus rendering the 3000 Hz polling functionally equivalent to 1000 Hz polling. In fact, 2000 Hz polling is also no different from 3000 Hz polling. Accordingly, I'll stick with 1000 Hz for the remainder of my testing.


Mad Catz has reached out to me and is adamant that the 3000 Hz is indeed real. While I'm still confident in my findings, I want to provide this perspective as well. The above shot of an oscilloscope reading has been given to me as evidence.

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 R.A.T. Pro X3 Supreme is moved first and thus receives a slight head start.


First, I'm looking at two xCounts plots—generated at 1600 and 3200 CPI—to quickly gauge whether there is any smoothing, which would be indicated by any visible "kinks." 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 R.A.T. Pro X3 Supreme is performing as expected. We can also see moderate SPI timing jitter.


In order to determine motion delay, I'm looking at xSum plots generated at 1600 and 3200 CPI. The line further to the left denotes the sensor with less motion delay. Whereas 1600 CPI shows no difference in motion delay, the R.A.T. Pro X3 Supreme is behind by roughly 4 ms in the 3200 CPI plot, which merely confirms the results above.

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 no sign of the sensor malfunctioning can be observed.

Polling Rate Stability

All three available polling rates (125 Hz, 250 Hz, 500 Hz, and 1000 Hz) look nice and stable. Polling stability is unaffected by any of the available RGB settings.

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. 3200 CPI has the first level of smoothing applied and shows no jitter, either. 16,000 CPI has major jitter despite the ridiculous amount of smoothing present at that step. Lastly, there is no sensor lens movement.

Lift-off Distance

The R.A.T. Pro X3 Supreme provides two pre-defined LOD levels to choose from and the ability to perform a manual calibration. At the "2 mm" setting, the sensor does not track at a height of 1 DVD (<1.2 mm). At the "3 mm" setting, 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). 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. As I found no way to open the mouse, I had to rely on the less accurate and reliable "bump test." Click latency has been measured to be in the range of +4.5–5.5 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.