Sensor

The eye of the mouse is manufactured by PixArt and codenamed PAW3389PRO-MS, which indicates some sort of customization involved from Microsoft's side. However, the sensor works exactly as a standard PMW3389 would, at least from what I could measure. This sensor is great and what you would expect from a high-end optical sensor: raw, snappy, and pinpoint accurate.

The main specifications of this sensor are 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 16,000 in steps of 50 CPI. Its available polling rates are 125, 500, and 1000, which translates into nominal response times of 8 ms, 2 ms, and 1 ms. There are two pre-configured lift-off distance options, 2 mm and 3 mm. You can also create a total of three custom LOD settings using the software's surface calibration.

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 Pro IntelliMouse is great; it's pretty much pitch-perfect on the lower values and only increases slightly at higher resolutions.

Perfect Control Speed

Perfect control speed (or PCS for short) is brutally high on this sensor. There is absolutely no way of hitting it while gaming with even incredibly low in-game sensitivity. The nominal perfect control speed is 400 IPS, which is about 10.16 meters per second. The PCS values don't correlate with the set resolution, which means 100 and 16,000 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 in this test is almost entirely caused by human error.

Polling Rate

All polling rate values seem nice and stable since there are no suspicious periodic drops or other sorts of outliers.

Input Lag & Smoothing

There is no input lag or detectable smoothing below 1,900 CPI. On and above this value, smoothing kicks in, which results in about +2 ms of input lag until the 6,000 CPI step, where it goes up to about +4 ms. Upon reaching the maximum resolution, smoothing increases to approximately +7 ms of input lag. I'd definitely recommend staying below 1,900 CPI for competitive online gaming.

Click Latency

Click latency is roughly +5.9 ms when compared to the SteelSeries Ikari, which is considered as the baseline with 0 ms. The data comes from this thread and my own testings. Testing was done with a Logitech G203 and the Pro IntelliMouse, using qsxcv's program.