Mouse polling rate and DPI: what each number changes

DPI (dots per inch, also written CPI for counts per inch) is the number of movement counts the sensor reports for every inch the mouse travels. At 800 DPI, moving the mouse one inch sends 800 counts; at 1600 DPI it sends 1,600. The operating system and the game then turn those counts into cursor or crosshair movement.

That means DPI is a sensitivity dial, not a sharpness or accuracy rating. A mouse that tops out at 16,000 DPI is not necessarily more precise than one that stops at 8,000, because almost nobody runs a sensor near its ceiling. What is worth checking is whether the sensor stays consistent across the DPI steps you actually use, which a maker's spec sheet or an independent measurement can show and a headline maximum cannot.

To compare settings between mice or between games, multiply DPI by the in-game sensitivity value. A 800 DPI mouse at an in-game value of 0.5 gives the same effective sensitivity (400) as a 400 DPI mouse at 1.0, provided the game scales linearly. Many shooters publish their sensitivity formula, so look up the game rather than assuming.

Polling rate is measured in hertz. At 125 Hz the mouse reports every 8 ms, at 500 Hz every 2 ms and at 1000 Hz every 1 ms. Faster rates shorten the gap: 2000 Hz is 0.5 ms, 4000 Hz is 0.25 ms and 8000 Hz is 0.125 ms.

Going from 125 Hz to 1000 Hz is a visible change in how smooth a fast flick feels, because the cursor path is sampled far more often. Beyond 1000 Hz the gains shrink quickly. The benefit depends on the display refresh rate, the game's input handling and how fast you move, so it is a conditional upgrade rather than a universal one.

Higher rates also cost something. Each report is a small interrupt for the CPU, and at 4000 or 8000 Hz that load can be noticeable in games that already push a processor hard. Wireless mice at high rates drain the battery faster, and the maker's stated battery life is usually quoted at a lower rate, so read which setting the figure refers to.