About one second, maybe less, but you can slow it down to about 2 seconds by half-pressing the trigger. Very good scissors in my opinion (non-professional use).
Great for thick branches and then it is also fast enough, with thin branches you are faster with the manual shears. Super shears, wouldn't want to be without them.
Difficult to say if fast is not defined. Let me put it this way, you can cut thin branches faster with hand shears. But I wouldn't want to do without the Worx, it's worth every franc!