My printer got faster overnight and I did not change a single piece of hardware. I changed where it thinks. That is the whole pitch for Klipper, and after a fortnight of running it I am a convert.
The board on a typical hobby printer is a little 8-bit microcontroller, and it is doing a lot: reading the gcode, planning every acceleration curve, and stepping the motors, all on a chip that would have felt slow in 1995. When you ask it to print fast with detailed moves, it simply cannot do the maths quickly enough, the move queue starves, and the printer stutters. You hear it: little pauses on tight curves where the planner ran out of road.
Klipper splits the job in two. The heavy thinking, all the motion planning, moves to a Raspberry Pi, which is an absurdly powerful computer to bolt to a printer. The printer's own board gets reflashed with Klipper firmware and demoted to a dumb but precise step generator: the Pi works out exactly when every step pulse should fire, sends that timetable down, and the microcontroller just executes it on schedule. The slow chip stops trying to think and gets very good at doing as it is told.
The result was immediately obvious. Curves that used to stutter came out smooth because the planner never starves now. I pushed speeds up and the quality held. And the configuration is a single readable text file rather than recompiling Marlin and reflashing every time you want to nudge a setting:
[printer]
kinematics: cartesian
max_velocity: 300
max_accel: 3000
[stepper_x]
step_pin: PD7
rotation_distance: 40
Change a number, type RESTART, done. No toolchain, no firmware build, no waiting.
It is not entirely free. You are adding a Raspberry Pi and some wiring to a machine that worked fine, and the first setup involves flashing the board over its serial connection, which is fiddly the first time. But what you get is a printer that punches well above its hardware, tuned through a config file instead of a compiler. For a machine I had quietly decided was as fast as it was going to get, that was a genuinely good afternoon's work.