Razer Viper V4 Pro Review

At Razer, the Viper Pro line is the one for light mice aimed at the most demanding players, and the V4 is here to raise the bar again with a lower weight — 49 grams — and a new Focus Pro 50K sensor. Enough to justify a suitably high-end price? This review is based on that published test, not on a hands-on trial of our own.

Launched after the excellent Viper v2 Pro, the Viper v3 Pro was praised by critics and players alike, and its many awards did not stop Razer planning a successor — so, roughly two years on, along comes the Viper v4 Pro. There is no attempt to reinvent a proven concept, only to refine and modernise it. At first glance the changes look slight, and the impression holds: the design is much the same, with the perfectly symmetrical shape and gentle indents at the sides. The mouse is fairly compact — 127.1mm long, 63.9mm wide and 39.9mm thick — strictly identical to the Viper v3 Pro.

While keeping its predecessor's shape and dimensions, the Viper v4 Pro makes an effort on weight, shedding exactly 5 grams; it may sound minor, but it drops the mouse below the 50-gram mark, which is far from common for a wireless model. There is no honeycomb shell here, as on some ultralight designs, and at no point does the build feel anything but high quality — the materials exude it. There is the usual bidirectional wheel and two thumb buttons alongside the main clicks; underneath sit a button to power the mouse and change sensitivity, plus two large PTFE feet for glide. A USB-C port completes the picture, and a small puck handles the wireless link while doubling as a charging dock.

Those five grams will delight eSport players without altering the silhouette, but the spec sheet moves on markedly, starting with a much-boosted sensor: the third-generation Focus Pro climbs to 50,000 dots per inch, against 35,000 on the previous model. Designed in-house at Razer, it is also rated for 930 IPS maximum speed and 90G of acceleration. The switches are more durable too, rated at 100 million clicks for this fourth generation — 10 million more than the third.

Razer has worked on connectivity as well. Bluetooth is absent — a shame — but there is an "optimised" HyperSpeed wireless link designed to cut the risk of signal loss while trimming latency further, measured against the standard of a wired connection; the USB cable is mainly for charging but can also run the mouse. There is no change to the polling rate, though Razer already ranks among the best here, reaching up to 8,000 Hz — useful only to the very finest players, and adjustable, like the sensor's sensitivity, from Razer's software.

Those adjustments are made through the Synapse Web interface which, as on most recent Razer peripherals, replaces the Synapse app. Moving to a browser-based tool is a nod to simplicity — nothing to install, and settings reachable from any connected machine — and, reassuringly, one profile is stored in the mouse's own memory should the internet drop. Everything can be customised, primary and secondary (Hypershift) functions alike; sensitivity is adjustable from 100 to 50,000 dpi in 100-dpi steps, and the polling rate can be set to 125, 500, 1,000, 2,000, 4,000 or 8,000 Hz, alongside sleep and low-power options. A "dynamic sensitivity" setting tailors acceleration to your habits, a rotation adjustment keeps horizontal movement straight whatever your grip, and the puck's LEDs can display battery level, polling rate or sensitivity.

The Viper v4 Pro's dimensions suit a broad audience — small, medium or large hands are all catered for — and palm, claw and fingertip grips are all possible, with two optional stick-on grips supplied for extra purchase. Even after hours of play there is no fatigue; the buttons are ideally placed, the only quibble being the sensitivity button underneath, which is not the handiest spot, though one rarely changes setting mid-match. Comfortable, reactive and precise, the mouse never drops its connection.

Battery life is the standout. Razer has doubled the Viper v3 Pro's 95-hour maximum to a remarkable 180 hours, and even at 8,000 Hz the endurance is startling, with 45 hours confirmed in testing. There are, though, three fair criticisms. Despite the seemingly ambidextrous shape, the thumb-button placement makes this a right-handers' mouse only. The optical scroll wheel can take some getting used to — precision and responsiveness are not in doubt, but the detents are a touch too soft. And the switches are a little "clicky" and noisy, which, like the wheel, comes down to personal preference.

Once again Razer has produced an exceptional mouse and, once again, one reserved for a well-heeled elite — few players will want to spend this much on a mouse, however modern and capable it is. Beyond the price, though, this is another very good product: the Viper v3 Pro was already a benchmark, and the v4 Pro pushes the sliders further still, with a more sensitive sensor, better wireless and far greater battery life, and a feel that improves a little too. If you liked the v3 Pro, you will like its successor: the same shape and dimensions, but lighter for an even better hold, aided by the optional grips. No major innovation, then, but progress on every front — and surely another hit for the brand.