Real player's speed is based on a system called SPEED BREAKPOINTS.
Sometimes our characters won't be faster even if we gonna wear speed equipment. There is a reason for that. That's mean we didn't reach next speed breakpoint for a specific type of ground. Below we have a table showing when we can reach breakpoints:
There is also a formula to calculate breakpoint:
Real movement speed = P/(100/T)
P - Player's speed
T- tile's walking speed
It's good to know also that if we use speed spell, our speed stats may give a fractional number, for example - 319.6 (Client will show 319). In that case, our true speed will be 320, because the client is round it up by 0,5.