At a pointer speed setting of 6/11, for every one mouse count your computer will move the pointer one pixel on your screen, a 1:1 ratio.[2] If the mouse pointer speed it set higher or lower than 6, Windows will artificially modify the mouse input. For instance, at the 7/11 mark, your computer moves the cursor 1.5 pixels for every one mouse count and at the 11/11 mark, your pointer moves 3.5 pixels for every one mouse count. This means that not only does Windows skip pixels, it actually can become impossible for the mouse cursor to land on certain columns. Conversely if you have your slider at the 5/11 mark, your pointer will move .75 pixels for every one mouse count. Since computers cannot show 1.5 pixels, it rounds to either 1 or 2 making uneven mouse movements. While a speed setting of 6/11 is the absolute ideal, by keeping it at an even number such as 2/11, 4/11, 8/11 or 10/11 will reduce the impact of Window's manipulation of the input. This is because the odd numbers have to be rounded off. Zdroj