Hmmm, don't recall exactly.. but fast
I use 1/2" ball nose for roughing and finishing. Roughing was at 10 or 11 ips at .5" depth. Finish I believe was 8 ips with a 15% step. A bit of sanding and the mill marks are gone.
But, every job is different. My molds are typically long smooth curves, really lets me crank up the speed.