Guys, what causes mouse cursor speed on hardware level?

[NewbieOneKenobi]

Is it just dpi or does fps (or whatever the sensor is using) have something to say in the matter? Will an old 400 dpi M$ mouse run slower than an 800 dpi Logitech? (Assuming no drivers, no change in sensitivity sliders, no nothing.)

One reason I'm asking is the opportunity to get M$ Wheelmouse 1.1 for cheap near me (they're having a sale) but it says 400 dpi...

And I mean speed rather than sensitivity (and not acceleration either).

[woody]

DPI is DPI. There is cap at acceleration, but it's unrelated.
Interval at which the mouse sends relative movement varies. I have seen it named "polling rate". Varies probably between 125 Hz ... 1 kHz for USB.

[NewbieOneKenobi]

Thanks, guys. Also, am I seeing things or do laser mice tend to move the cursor faster than optical ones at the same dpi?