Hi guys, My first post here, looking for collective wisdom to help me with my setup: Hemera Direct + Vulcano + 0.8mm nozzle SKR 1.3 + TMC2226 + Marlin 2.0.9 Extruder Stepper in SpredSpectrum mode rest in StealthChop SuperSlicer Pronterface Extruder is calibrated, PID is calibrated. Looks like when printing anything faster then 40 mm/s it comes up underextruded on top surfaces ( with holes etc ) Can correctly extrude 100mm of PETG ( 230C ) with 760mm/m(12.6mm/s) extrusion speed via 0.8 nozzle Anything more then 760 - underextrudes ! Cannot perform Marlin Linear Advance test properly, it just looks like crap. as I see only lines extruded at 20mm/s rest is not existent. In same time my stock RigidBot Big (another printer) with very dated A4988 driver and its original dated and low-tech extruder + 0.5mm Vulcano ) can do easily 70 mm/s with the same model and looks much better ! Is there any current requirement for Extruder driver ( I currently using marlin default AFAIK it is set to 800ma ) Is there anything else I have to take a look ? I understand it is very broad problem... but may be I'm missing something?