Printer model
MK4S
Firmware version
6.5.3
Upgrades and modifications
MMU3
Printing from...
Prusaconnect and prusalink
Describe the bug
Video here: https://photos.app.goo.gl/1PEqTBDUY3Eu14Hs7
MK4S undergoes drastic slowdowns when printing corners using the adaptive pressure advance feature from orcaslicer. Print times are increased by 40% for models with a lot of line-width variations (eg filleted corners).
I generated a simple cylinder to print and inserted meaningless changes in the pressure advance for a few layers. The section where the PA is changing is clearly visible.
G1 X125.108 Y92.778 E.13002 ; perimeter
M900 K0.056; Override pressure advance value
G1 X127.541 Y93.043 E.14233 ; perimeter
M900 K0.057; Override pressure advance value
G1 X129.972 Y93.833 E.14862 ; perimeter
M900 K0.056; Override pressure advance value
G1 X132.187 Y95.112 E.14873 ; perimeter
M900 K0.057; Override pressure advance value
This is the pressure advance view in the slicer (I exaggerated the changes to visualise them)
If I find & replace instances of M900 K with M572 S the effect is the same.
2026-06-05 0019 M900KandM572S_3000acc_LH0.3mm_Cylinder_0.6g_PETG_MK4S_2m1s.gcode.txt
I believe that this problem only arose in 6.5.3 of the firmware.
How to reproduce
Generate any model file with many PA changes through the model.
To most effectively see the impact, add miniscule changes to PA to the walls of a cylinder to see the delay it introduces and subsequent extrusion artefacts.
Expected behavior
The printer should move smoothly when pressure advance is changed using either legacy M900 or contemporary M572
Files
Here is a video of the printer hanging during a print: https://photos.app.goo.gl/Voi2Ja4JBSjtQYty9
* The artefacts also disappear if the M900 commands all have the same value (eg the PA doesn't actually change).
Printer model
MK4S
Firmware version
6.5.3
Upgrades and modifications
MMU3
Printing from...
Prusaconnect and prusalink
Describe the bug
Video here: https://photos.app.goo.gl/1PEqTBDUY3Eu14Hs7
MK4S undergoes drastic slowdowns when printing corners using the adaptive pressure advance feature from orcaslicer. Print times are increased by 40% for models with a lot of line-width variations (eg filleted corners).
I generated a simple cylinder to print and inserted meaningless changes in the pressure advance for a few layers. The section where the PA is changing is clearly visible.
This is the pressure advance view in the slicer (I exaggerated the changes to visualise them)
If I find & replace instances of
M900 KwithM572 Sthe effect is the same.2026-06-05 0019 M900KandM572S_3000acc_LH0.3mm_Cylinder_0.6g_PETG_MK4S_2m1s.gcode.txt
I believe that this problem only arose in 6.5.3 of the firmware.
How to reproduce
Generate any model file with many PA changes through the model.
To most effectively see the impact, add miniscule changes to PA to the walls of a cylinder to see the delay it introduces and subsequent extrusion artefacts.
Expected behavior
The printer should move smoothly when pressure advance is changed using either legacy M900 or contemporary M572
Files
Here is a video of the printer hanging during a print: https://photos.app.goo.gl/Voi2Ja4JBSjtQYty9
* The artefacts also disappear if the M900 commands all have the same value (eg the PA doesn't actually change).