I would certainly expect faster than that if it is 1:1, my Bridgeport has steppers with 2.5:1 reduction and I get 2500mm/min on all axis so would think you should be looking at atleast 5000mm/min as I doubt its any heavier. Not sure what size steppers you have as its hard to say from a pic but look like they are about 916oz/in. What drives are you using and what is the stepping on them?
Hood