Although my print head can move at 300 mm/sec, my extruder can not reliably keep the plastic flowing at that speed. (Perhaps if I turned up my extruder temperature above 195 C…)
I have decided that 275 mm / sec is a reliable top speed for my extruder after printing a relatively large part at that speed with the temperature turned up to 200 C.
This video shows layers being printed in about 15 seconds with 3 exterior perimeters and 25% infill.
Here is another video of the twisted koch snowflake vase (scaled up to 150%) being printed at 275 mm/sec top speed. Due to the fractal nature of the sides of the vase the platform rarely got up to the top speed, as it never had a long enough path to accelerate up to full speed.