Sensor and Performance

The SteelSeries Prime Mini Wireless is equipped with the TrueMove Air, which I believe to be a customized PixArt PAW3335. According to specifications, the TrueMove Air is capable of up to 18,000 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: 400, 800, 1200, 2400, and 3200.

All testing was done on the latest firmware. As such, results obtained on earlier firmware versions may differ from those presented hereafter.

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, inconsistent, and very significant. A poor result overall. In order to account for the measured deviation, adjusted steps of 400, 800, 1500, and 3000 CPI have been used for testing, even though the 800 CPI step in particular is equally off at 800 and 700 CPI (nominally) to where getting an accurate 800 CPI is impossible, and the same goes for 400 CPI. In general, CPI adjustment is not consistent at all, leading to cases where two steps that are only apart by 100 CPI nominally end up deviating by roughly twice as much in practice.

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 G403 is moved first and thus receives a slight head start.

Wired testing

First, I'm looking at two xCounts plots—generated at 1600 and 18,000 CPI—to quickly gauge whether there is any smoothing, which would be indicated by any visible "kinks." As you can see, no such kinks are in sight, which confirms that there is no smoothing across the entire CPI range.


In order to determine motion delay, I'm looking at xSum plots generated at 1600 and 18,000 CPI. The line further to the left denotes the sensor with less motion delay. Neither 1600 nor 18,000 CPI show any motion delay differential, which confirms that there is no smoothing. The behavior commonly seen on wireless implementations of the 3335 whereby motion latency is greater at the onset of motion essentially is not present.

Wireless testing

Not much changes when running the Prime Mini Wireless in wireless mode. 18,000 CPI still does not show any kinks indicative of smoothing, and SPI timing jitter and general tracking are virtually on the same level as when wired.


Keeping the motion delay differential in wired mode established above in mind, I can measure a wireless delay of roughly 1 ms.

Speed-related Accuracy Variance (SRAV)

What people typically mean when they talk about "acceleration" is speed-related accuracy variance (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 5 m/s, which is within the proclaimed PCS range and results in no observable sign of the sensor malfunctioning.

Polling Rate Stability

Considering the Prime Mini Wireless is usable as a regular wired mouse as well, I'll be testing polling rate stability for both wired and wireless use.

Wired testing


All four available polling rates (125/250/500/1000 Hz) look nice and stable. However, every once in a while, outliers creep in, as seen below. Polling stability is unaffected by any RGB lighting effect.


I'm unable to reproduce this behavior consistently.

Wireless testing
For wired mice, polling rate stability merely concerns the wired connection between the mouse (SPI communication) and the USB. For wireless mice, another device that needs to be kept in sync between the first two is added to the mix: the wireless dongle/wireless receiver. I'm unable to measure all stages of the entire end-to-end signal chain individually, so testing polling-rate stability at the endpoint (the USB) has to suffice here.


First, I'm testing whether SPI, wireless, and USB communication are synchronized. Any of these being out of sync would be indicated by at least one 2 ms report, which would be the result of any desynchronization drift accumulated over time. While there are several off-period polls, I'm unable to determine whether these are due to drift or caused by something else.



Second, I'm testing the general polling-rate stability of the individual polling rates in wireless mode. Running the Prime Mini Wireless at a lower polling rate can have the benefit of extending battery life. As you can see, all of the four available polling rates look stable, though much like in wired mode, occasional outliers make an appearance, as seen below. Polling stability is unaffected by any RGB lighting effect.


Once again, I'm unable to reproduce this behavior consistently.

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 or 3200 CPI. At 10,000 CPI, jitter is already significant, and reaches ridiculous levels at 18,000 CPI. This is within expectations for a sensor lacking any smoothing. Lastly, there is no sensor lens movement.

Lift-off Distance

The Prime Mini Wireless does not have any LOD adjustment options. This is unfortunate as the 3335 would be fully capable of it. By default, the sensor tracks only intermittently 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

Most gaming mice use mechanical switches for their buttons. By wiring the switches of the test subject together with the switches of a control subject, I'm able to measure click latency very accurately; i.e., standard error of around 0.05 ms. However, this method is not applicable to mice with non-mechanical switches and wireless-only mice in general. As such, other methods ought to be employed, one of which is NVIDIA's Latency Display Analysis Tool (LDAT). The LDAT allows me to measure the entire end-to-end latency between the mouse click and photon transition on the monitor. By establishing the relative difference to a control subject, I'm able to provide values I consider sufficiently accurate; i.e., standard error of around 0.2 ms. Many thanks go to NVIDIA for providing me an LDAT v2 device.

Click latency has been measured to be roughly +11.0 ms when compared to the Razer Viper 8K, which is considered as the baseline with 0 ms. Standard deviation is 2.5 ms, but since the indicated value is neither the absolute click latency nor the measured end-to-end-latency, standard deviation ends up looking disproportionally large. Comparison data comes from my own testing and has been exclusively gathered with the LDAT.