Sensor

While the other two new Corsair mice came with all-new, high-end optical sensors, the Harpoon RGB Wireless goes for something more modest. The PixArt PMW3325 is a great sensor; it's accurate, raw, and responsive, but comes with a few quirks, as can be seen in the tests. However, there is a very good reason Corsair used this sensor: the PMW3325 is much more power (and cost) efficient than the PMW3391 or any similar high-end sensor.

Now for the sensor's specifications: the maximum nominal tracking speed and acceleration values are 100 IPS and 20 G. You can set the resolution from 200 to 5,000 CPI in increments of 100 CPI (the specifications say the maximum amount is 10,000 CPI, but the maximum amount in the software is 5,000—you really shouldn't use anything higher than that, especially with this sensor). 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 lift-off distance is rather high since the sensor still tracks from two DVDs in height, which is roughly 2.4 mm. Unfortunately, there is no option to adjust this, which is one of the weak points of the PMW3325 sensor.

Battery, Wireless Stats

The Harpoon RGB Wireless has a built-in 850 mAh lithium-polymer (Li-Po) battery that can be charged with the cable that comes with the mouse. Of course, the mouse can operate while charging. The battery can last up to 60 hours with a single charge in Bluetooth mode and about 45 hours in 2.4 GHz mode without lighting enabled. With lighting, these values drop down to 40 hours and 30 hours. The total charging time is about 2 hours from a fully drained state. Bluetooth mode has about 7.5 ms latency. You can change modes (2.4 GHz, off, and BT) with a three-way switch next to the bottom-left mouse skate. The standard wireless connection uses Corsair's Slipstream technology.

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 Harpoon RGB Wireless is similar to other PMW3325-equipped mice, which means it's positive at first and then moves into the negative, but the deviations are quite negligible.

Perfect Control Speed

While the nominal perfect control speed is only 100 IPS, or 2.54 m/s, the actual value is much higher; the sensor stops tracking at 3.6 m/s. This should be more than enough for most gamers. However, if you play at a very low sensitivity (I would say 60 cm/360° or lower), this mouse might not be your best choice. I play with about 50 cm/360° and had no issues; this sensor didn't spin out once during some CS:GO and Quake Live action.

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

Input Lag & Smoothing

Warning, deep waters ahead! Wireless means 2.4 GHz here, Bluetooth wasn't tested. The wireless receiver dongle was approx. 15 cm away from the mouse during testing.

On the first two graphs, you can see sensor counts with a single swipe to the right. There are small kinks in both graphs, right at their beginnings, which indicate that the mouse has some smoothing on all CPI levels. These small kinks are there both when the mouse is in wireless and wired mode. On the next graphs, you can see the input lag, in comparison to the Ninox Venator at 800 CPI. All CPI values show about +2.5 ms of input lag; again, both when in wireless and wired mode.

This leads me to conclude that either the mouse pretty much has zero wireless input lag and only has some MCU smoothing added, or the mouse indeed has about +2.5 ms of input lag in wireless mode, which is "compensated" for by added smoothing when it's wired. Honestly, I think the first explanation makes more sense as the kinks in the xCount graphs are indicative of this as well. I don't know the reason behind this. It's either a bug in the firmware or deliberately there for some reason. The PMW3325 sensor shouldn't have as much smoothing by default, so I'm pretty sure it's MCU-related. I have contacted Corsair about this and will update the review based on their answer.

All in all, this amount can be considered negligible, depending on your PC setup and which games you are playing on which level. For casual offline and online gaming or even some higher-level stuff, such as CS:GO, Quake, League of Legends, etc., it's perfectly suitable. I was barely able to detect any motion delay, and I have been in the gaming business for quite some time, I have a 144 Hz monitor and a stable framerate. Again, this is a very intuitive thing as well; if you are sensitive to any kind of extra latency, then this mouse might not be your ideal companion.