It depends on material, cutter, etc...... I cut foam at 120-170 IPM no problem... I could cut faster than that if I preffered but do not. To do so woukld be of - I just have to set the accel rates so as not to start oscilating the machine too much.
Feel free to ask more about the subject if you like.
Im not sure the MAX I can get - I really have not tried to max it out......
I have run it at 250 IPM no load and much faster though Im not sure just how fast but it was moving fast enough that it made you think hard about leaning near the machine ! It was probobly around 400 IPM.... no load
As far as cutting speed in 1" The machine can go 100 IPM EASY, or 150 IPM easy or more - the problem is the ROUTER- Im not really sure how fast it can cut, and Im not going to 'push' my machine to find out....... you have to have a router that can cut as fast as the machine is moving or it stalls out and burns up your router. The thick stuff (1") I have cut I cut at about 70 IPM and did in 2 passes because I was looking for high accuracy of the finished part - I cut oak plywood like this and also Gabon plywood - a 12 ply plywood for boatbuilding...... very hard stuff...... I cut it with a 1/2" bit, 10,000 RPM
I have not pushed the limits.... I built the machine to make good accurate parts ... I didnt design it with all out speed in mind..... remember to have pure speed, you also must have more mass..... as a gantry changes direction it starts to cause oscillations - in rapid short strokes with high accel rates you can really get a CNC machine bouncing........ so remember, you can build a great machine and realize its not going to cut as fast as a 100,000 machine because it doesnt have the mass... You could build the Cad Cut machine and build it with 4" steel to increase the mass, put servos on it, and crank it up yes...... but you need to be realistic... you can build this machine for half of buying anything simular as an OEM machine and have everybit as good a machine.....
I hope I helped with my answer..... Im sorry I dont really have the 'max limits' The machine does great for me..... and I dont want to find out its 'top speed' at the risk of damage.... for what I do its a fantastic machine....... it can make a part in 20 minutes that would take me 8 hours to do the way I used to do it......