"Yet another feature of the MX series is the 800dpi resolution, apparently twice that of competing mice (whatever those may be). This basically means that ideally for every 1 inch the mouse moves, the cursor will travel 800 pixels on the screen. Of course there are more factors to this in the way of user preferences and speed/acceleration, but a higher dpi corresponds to more precise movements. With a monitor capable of supporting high resolutions, you'll notice that you'll have to physically move the mouse a lot more to get across a 1600x1200 screen than one at 800x600. Needless to say, this can be very uncomfortable. Software compensates for this using the aforementioned settings, but the problem arises when pixels are skipped to achieve the desired speed. For instance, using "standard" acceleration, if your mouse has 400dpi resolution and you want it to move 800 pixels for every inch, it'll end up skipping every other pixel. While this may seem trivial, if you use 1600x1200 resolution and have small icons and even smaller text, you may run into some difficulties trying to select them."