My printer is not a good printer. It is a budget bedslinger I bought years ago to find out whether I would actually use one, and the honest answer turned out to be yes, slowly. The frame flexes, the stock board is underpowered, and anything above a gentle pace produced ghosting that looked like the part had been printed during an earthquake.
So I expected to replace it. Instead I moved it to Klipper, and it is now genuinely quick, on the same motors and the same frame I was about to throw out.
what actually changed
The trick is that Klipper does the heavy maths on a Raspberry Pi rather than the little microcontroller on the printer. The board just drives the steppers. That alone lets you push higher acceleration without the firmware choking. But the part that made my jaw drop was input shaping.
I taped a cheap accelerometer to the toolhead, ran the calibration, and Klipper measured the exact resonant frequencies of my wobbly frame. Then it shapes the motion commands to avoid exciting them. The ghosting did not improve, it vanished.
[input_shaper]
shaper_freq_x: 41.2
shaper_type_x: mzv
shaper_freq_y: 33.8
shaper_type_y: ev
Two numbers, measured rather than guessed, and the rattle was gone.
The other win is pressure advance, which fixes the little blobs at corners by easing off the extruder before the toolhead slows down. On Marlin I had fiddled with this by eye for an afternoon and given up. On Klipper you print a single test tower, read a value off it, and you are done.
the cost, because there is always one
It is not free. The configuration lives in a text file you will edit a lot, and the first evening is spent getting the Pi talking to the board over USB and not much else. If your idea of a good time is a printer that Just Works out of a box, this is not that. You are trading convenience for control, and you need to want the control.
I did. My benchy now prints in roughly half the time it used to, at better quality, and I have spent nothing but a weekend and the price of an accelerometer. The printer I was ready to bin is suddenly the most capable thing on the shelf, which is a deeply annoying outcome to be this pleased about.