Sensor

PixArt PMW3391—ever heard of it? Me neither! This is Corsair's "own" sensor, which is based on the PixArt PMW3389. It's an absolutely high-end optical sensor; it's raw, responsive, and pinpoint-accurate with a ridiculously high perfect control speed. I encountered no anomalies, spin-outs, or any errors while testing and playing high-paced FPS games with the mouse.

The specifications of this sensor are nearly identical to the PMW3389; the nominal acceleration and maximum tracking speed values are 50 G and 400 IPS (10.16 m/s). You can set the resolution from 100 to 18,000 in steps of 1 CPI, which is unique as up until now, the lowest step was 50. The available polling rates are 125, 250, 500, and 1000, which translates into nominal response times of 8 ms, 4 ms, 2 ms, and 1 ms. The default lift-off distance is pretty high as the mouse is calibrated for Corsair pads, but with the surface calibration in the software, I could bring it down to below 1 DVD in height.

Paint Test

There is no jitter on the reasonable CPI steps, unwanted angle snapping (you can turn this on in the software, but I would highly advise against it), or sensor lens rattle.

CPI Divergence

CPI divergence on the M65 RGB Elite is pretty low, but if you come from a mouse with pitch-perfect CPI accuracy, you might have to adjust your in-game sensitivity accordingly.

Perfect Control Speed

Perfect control speed (or PCS for short) is very high on the PMW3391—there is no way of hitting this value while gaming, even with incredibly low in-game sensitivity. The nominal perfect control speed is 400 IPS, which translate to about 10.16 meters per second. The PCS values don't correlate with the set resolution, which means 100 and 18,000 CPI both hit their limits at about the same value.

Speed Related Accuracy Variance

This test shows the sensor's accuracy at different speeds. You can see me doing a fast swipe to the right before I slowly slide the mouse back to its original position. There is no acceleration or deceleration; any displacement is almost entirely caused by human error in this test.

Polling Rate

All polling rate values seem normal since there are no suspicious periodic drops or other sorts of outliers. At 1000 Hz, there are some high spikes, but all my mice have these on the latest Windows 10 versions, on all mouse pads I own. This is strange, but as of now, I have found no fix, and it honestly doesn't really seem to affect anything in game.

Input Lag & Smoothing

There is no input lag or detectable smoothing with this sensor. The first two graphs show counts; these should have subtle or harsh kinks if there's any smoothing. The last four graphs indicate the input lag, which can be considered nonexistent. I've done several tests with the Ninox Venator and G PRO Wireless as well. There were fast, medium, and slow swipes, and the results were consistently like these.

Click Latency

The click latency is roughly +3.2 ms compared to the SteelSeries Ikari, which is considered as a baseline with 0 ms. The data comes from this thread and my own testings. Testing was done with a Logitech G102 and the M65 Elite, using qsxcv's program.