Hmmm. A lot to cover. Board, step rate, resolution of your file, SD/Pi/USB, firmware version?
A test a while back with with Omri’s files showed USB was faster than the SD. On a ramps/LCD stack (32nd stepping). Not sure about the V1Pivs USB, I assume it is the same or slightly slower.
Arc’s should free up a ton of lines of code…but there are firmware versions that do glitch with arcs, the current one should be fine though.
Now if you are talking lasers…a whole new ballgame. The inline commands seem to choke things up a bit. 28mm/s for 32 bit, 22mm/s 8bit…so that is odd, not what you would expect but the tests verified that a while back. I assume that is a SD limit so TFT vs LCD pipeline, not an actual processor test.