MAME for Xbox - controls query

[Spector]

Why is it that MAME on the Xbox has such sluggish controls? I think that the majority of games (if not every game) has this problem. If you, for example, press the fire button when playing Bomb Jack to make your character jump, he only starts the jump when you have released the button a brief moment later, not when you press it. There is a delay between the control pad action and the movement on screen that the original games do not have.

 

Why is this? The rhythm of a game comes from the pressing of buttons synching with the movement on screen. The slight delay kills this and is irritating. It would seem to be such a simple problem to solve, yet it's there in possibly all the games I've played. MAME is not the only emulator with this strange effect on this console. So why the slow responsiveness in Xbox MAME?