Logitech's MX Master 4 Adds a Buzzing Thumb Panel and 9 Grams Over the 3S, With the Same 8,000 DPI Sensor

The MX Master 4 weighs 9 grams more than the MX Master 3S and doesn’t track any finer. Logitech’s spec page for the 4 says 150 grams and a 200 to 8,000 DPI range, and its page for the 3S says 141 grams and the same range. If you were waiting for a sharper sensor, there isn’t one.

What you get for the nine grams is a vibration motor. The 4 has what Logitech calls a “Haptic Sense Panel” under the thumb, and the company’s haptics help page says it buzzes to confirm certain actions. It’s on by default. A mouse that finally gives you feedback, and it’s about itself.

The list of what triggers it is shorter than you’d guess. Per that page, the panel buzzes when you move between bubbles in the Actions Ring and when you trigger one, on each step of a Smart Action you choose to give a buzz, when you hold the gesture button and move left, right, up or down, when it searches for a host or first pairs over Bluetooth, and when it powers on. Switching screens can buzz too, but that’s off by default. Gesture Click doesn’t buzz at all. Beyond that, the page says only specific app events trigger haptics and only some plugins support them, and it sends you to the Logitech Marketplace to find which.

Four intensity levels run from Subtle to High. Notebookcheck’s review, which found the feedback “pleasant and valuable,” notes the vibration stays in the thumb area and works best in apps such as Photoshop or Premiere Pro. There’s also a catch for the road: a battery-saving setting turns haptics off at 10% charge, and you have to switch that toggle off to keep them.

The rest of the hardware moved a little. The 4 measures 128.15 by 88.35 by 50.8 millimeters, and the 3S measures 124.9 by 84.3 by 51, so the new one is taller and wider by a few millimeters. The 4’s battery is rated at 650 mAh, up from the 3S’s 500 mAh. Both pages list about three hours of use from a one-minute charge, and the 4 is rated for about 70 days on a full one. The 3S page doesn’t give a days figure, so there’s no like-for-like claim there.

Then there’s the price. Logitech’s store lists the 4 at $119.99. Logitech’s store lists the 3S at $99.99. The Gadgeteer, reviewing the MX Master 4 Developer Edition, says the 3S runs $79.97 at Amazon, down from $99.99, and calls the difference “the real decision in this family.” It also says the 3S “keeps the shape, the MagSpeed wheel and the 8,000 DPI sensor and drops the Haptic Sense Panel and the Actions Ring.” The reviewer’s call: pay for the 4 if you work heavily with shortcuts, and pick the 3S if all you want is a good scroll wheel.

Which apps will give the panel something to do is the open part. Logitech’s help page doesn’t name them.

The next fight in mice is over who writes the plugins. A haptic motor without apps behind it is a vibrating thumb rest. If creative apps and window managers ship Marketplace plugins that use it, the panel gets more useful on the same hardware, which is the quiet win of putting a motor in a mouse before there’s much for it to do. Expect the 3S to stay on shelves as the cheaper default until that happens.

Nine grams for a buzz.