zaebis,
I'm not exactly sure what the maximum feed rate could be. I'm guessing now, but it looks like it is configured in Mach3 to do about 40 to 60 inches per minute rapid. As for the fastest possible fee rate? I'm sure you could configure it to go a lot faster but, this can get tricky. It depends on many variables and would take a rather long list of questions.
I haven't messed with the feed rates on mine yet because the defaults are more than enough for what I am machining. I'm sure there are some on this forum that have tweaked their feed rates that could chime in.
-Greg