Sensor and Performance

The MSI Clutch GM41 Lightweight Wireless is equipped with the PixArt PAW3370. According to specifications, the 3370 is capable of up to 19,000 CPI, as well as a maximum tracking speed of 400 IPS, which equals 10.16 m/s. For the Clutch GM41 Lightweight Wireless, MSI upped the maximum CPI to 20,000, though this has to be specifically enabled within MSI Dragon Center. Out of the box, five pre-defined CPI steps are available: 400, 800, 1600, 3200, and 6400.

All testing was done on the latest firmware (0088). 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 minimal, which is an excellent result. Despite the 3370 allowing for CPI adjustment in increments of 50 up until 10,000 CPI, the software for the GM41 Wireless doesn't.

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 19,000 CPI—to quickly gauge whether there is any smoothing, which would be indicated by any visible "kinks." As you can see, such kinks are plainly on display in the second plot, indicating smoothing at 19,000 CPI. We can also see decently low SPI timing jitter.


Things change when enabling "Motion Sync," which is an option within MSI Dragon Center. Upon enabling, a message warning of higher power consumption is displayed, even when in wired mode. Motion Sync should not be confused with MotionSync as implemented by Razer on mice using the Focus+ sensor (PAW3399), which is a partially hardware-based solution, whereas Motion Sync is entirely firmware-based. As such, Motion Sync can be expected to be less effective at tightening SPI timing. Still, with Motion Sync enabled, plots look significantly tighter across the entire CPI range.



In order to determine motion delay, I'm looking at xSum plots generated at 1600 and 19,000 CPI. The line further to the left denotes the sensor with less motion delay. As you can see, the results are rather staggering. 1600 CPI has no smoothing, yet already shows a motion delay differential of 6–4 ms. As with other 3370 implementations, motion delay is greater at the onset of motion, but progressively lowers until reaching a minimum of delay (first row). 19,000 CPI shows an even greater delay, hovering around 14 ms (second row).



Most curious, however, is the behavior with Motion Sync enabled. Motion delay is cut down significantly, though it continues to be greater than desired or possible. At 1600 CPI, the motion delay differential is around 2.5–1.5 ms (first row). The first level of smoothing is applied at and above 6500 CPI, resulting in a motion delay differential of around 4.5 ms. The second level of smoothing is applied at and above 14,000 CPI, resulting in a motion delay differential of around 7 ms, which holds true all the way up to 19,000 CPI (second row).

Wireless Testing

Tracking is barely affected by the switch to wireless, which is commendable.


Motion Sync improves things even further, albeit at a higher power consumption.



As far as motion delay goes, results are inconclusive. The substantial delay observed in wired mode makes it difficult to determine the isolated wireless delay. Realistically, it could be anywhere between 1 and 2 ms. 1600 CPI shows an overall motion delay differential of 5–1.5 ms. 6500 CPI displays a motion delay differential of around 4.5 ms, and 14,000 CPI has a differential of roughly 8 ms.



Unlike in wired mode, not much changes with Motion Sync enabled in wireless mode. The motion delay differential is around 4–1 ms at 1600 CPI, around 4 ms at 6500 CPI, and around 8 ms at 14,000 CPI. In short, motion delay is marginally improved at best, although giving a fully confident assessment proves difficult due to motion delay behavior as a whole not being entirely consistent. Still, isolated wireless delay appears to be close to 1 ms considering these numbers.

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 4.5 m/s, which is within the proclaimed PCS range and shows no sign of the sensor malfunctioning.

Polling Rate Stability

Considering the Clutch GM41 Lightweight 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 of the available polling rate settings (125/250/500/1000 Hz) look and perform fine. Polling stability is seemingly unaffected by any RGB lighting effect, though I did notice the occasional outlier.

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. As you can see, no off-period polls are visible, which suggests there is no desynchronization present.



Second, I'm testing the general polling-rate stability of the individual polling rates in wireless mode. Running the GM41 Wireless at a lower polling rate can have the benefit of extending battery life. All available polling rates look and perform just fine.

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. The little jitter visible at 6400 CPI is taken care of at 6500 CPI, where smoothing is first applied. 19,000 CPI has the second level of smoothing and shows moderate to high jitter. Lastly, no sensor lens movement can be observed.

Lift-off Distance

The Clutch GM41 Lightweight Wireless allows choosing between two pre-defined LOD levels. At the "Low" setting, the sensor does not track at a height of 1 DVD. Using the "High" setting, the sensor does track at a height of 1 DVD, but not at a height of 2 DVDs (1.2 mm<x<2.4 mm, with x being 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. In wired mode, click latency has been measured to be roughly +2.3 ms when compared to the SteelSeries Ikari, which is considered as the baseline with 0 ms, with standard deviation being 0.62 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.

The main button switches were measured to be running at 1.92 V. I'm not aware of the voltage specifications of the Omron D2FC-F-K (60 M) (China) switches, but 1.92 V seems rather low to me, especially considering the fact that the same switches were running at 3.3 V in the wired GM41.