I've used this printer for the past year, and got good results lately after a good rebuild with new rollers, new extruder wheels, a better direct drive sistem, bigger fan for the mobo, high speed fan for the extruder, AliExpress extruder mechanism and a well optimized marlin 2 firmware.
I got excellent results with pla, petg, abs and tpu.
And after this, i turned on the speed, by curiosity.
It found its limits at:
3000mm/s(xy) Printing acceleration( from 450 stock)
1400(z)
5500(e)
5000(travel)
200mm/s max outer walls and top layers
350mm/s max inner walls
0.25 layer height
265-270c extruder temp
0.45mm outer lines
0.5mm inner ones
0.42 top layer
About 30 mm³/s volumetric on inner walls and 23 for other layers
I will post in the comments the results. Never thought this can be achieved by this printer
Some data
The part i printed took 43 minutes with solid infill with speed settings
And 3h and 48m with normal setting i got used to.
Usually 35-50mm/s speed and 10 volumetric flow