Some of the best gaming mice are secretly dropping DPI at low movement speeds

Some of the most popular gaming mice on the market aren't holding their set DPI when moved at very low speeds, according to YouTuber pandahling, with the issue traced to PixArt sensors — specifically the PAW3395, PAW3950, and PAW3399. The firmware feature responsible is a DPI downshift mechanism originally designed to stop cursor jitter when the mouse is stationary.

Pandahling breaks the problem into three types. The first is binary: if your DPI is set above 7,500 and you move the mouse very slowly, it drops down to that threshold. The second involves a firmware profile switch that still leaves most DPI settings vulnerable at low velocities. The third is the most widespread — it affects all three sensors at every DPI setting, not just high ones. Mice with PAW3950 sensors showed a 2–5% DPI downshift in testing, but the Viper V4 Pro — which uses a newer custom PixArt sensor — came in at a notably higher 8–10%. MouseTester graphs confirm it: the same distance traveled slowly registers fewer counts than when traveled quickly, so the software thinks the mouse never fully returned to its starting position.

The downshift feature exists for a legitimate reason — preventing phantom cursor movement when the mouse is sitting still. The issue is that intentional slow micro-adjustments, like holding an angle in a tactical shooter, can trigger the same behavior and deliver less sensitivity than the player dialed in. The problem was flagged on X a couple of years ago but only recently got wider attention through pandahling's video and MouseCast coverage.

Until manufacturers push a firmware fix, the practical advice is to keep DPI below 7,500 to at least avoid the more dramatic first two downshift types. For players already running low DPI — 800, for instance — the real-world impact is probably minimal. High-sensitivity players, and especially anyone running a Viper V4 Pro, have more reason to pay attention.