Sensor

With a price tag of $29.99, you probably won't expect a top optical sensor, like the PMW3360 or PMW3310. In this price range, most mice are equipped with mediocre sensors, or ones that are not really worth mentioning. The Iris Optical RGB, however, uses the PixArt PMW3325, which is an upgraded version of the PMW3320. Even though it's not high-end, it doesn't really have any flaws I could find, except for its perfect control speed not being too high—but more on that a bit later. The MCU is a 32-bit ARM Cortex-M0 based PT32C302 manufactured by Princeton Technology Corp.

The resolution can be set from 100 to 5,000 CPI in increments of 100 CPI. The available polling rates are 125, 250, 500, 1000, 1500, and 2000. There is an option to adjust the angle snapping, but for gaming, I would highly suggest turning it off. There are no options for lift-off-distance controlling, and the default value is just below 2 DVDs (2.4 mm) on a black cloth pad. It's a bit high, but again, this isn't a high-end sensor.

Paint Test

There is no jitter on the reasonable CPI steps, or unwanted angle snapping and measurable (or audible) sensor lens rattle.

CPI Divergence

The CPI accuracy is quite good; deviations are very small, almost negligible. It is a bit strange that the 400 CPI value is lower and the others are higher, but I measured all values five times, and it always led to the same result.

Perfect Control Speed

The PCS of the Iris Optical RGB is about 3.6–3.8 m/s. After hitting this speed, the sensor stops tracking and malfunctions; you will be looking at your legs in an FPS game, for instance. However, you should not be alarmed because hitting that range takes an awfully fast swipe. Unless you are playing on an extremely low sensitivity, you should not worry about it.

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.
Any displacement is almost entirely caused by human error in this test. I have also added two very fast swipes in the end to demonstrate what reaching malfunctioning speeds looks like.


Here's the same test done with the MouseTester software.

Polling Rate

The set polling rates are nice and stable until 1000 Hz. Above that value, MouseTester could not properly measure the values, but the averaging polling-rate checkers showed relatively correct values. It is very hard to measure this high of a frequency properly. I would honestly suggest staying on the 1000 Hz setting as I cannot see the reason behind going higher on even a 240 Hz screen with a stable 240+ FPS.

Input Lag

This is where the PMW3325 actually beats the current flagship, the PMW3360. The PMW3325 does not have any input lag on these CPI steps, while the PMW3360 (and its variants) will at least have +2 ms above 2000 CPI because of some added sensor smoothing. The control subject was a Ninox Venator at 800 CPI.