I was just trawling through some old posts by guru Richrap and I found this one: https://plus.google.com/+RichardHorne_RichRap3D/posts/M7KMXdvnXfV where, in one of the comments, he says: I'm now interested in why the extruder max speed is set slow (25mm/sec) I'm normally up at 32mm as a minimum, better if you can get to 38mm/sec for retractions. The first thing I realise is that "I'm an idiot" because all this time I've been naively playing with retraction speed in S3D wondering why it didn't make a difference! I checked on the LCD and max retraction speed is indeed set to 25mm/s (RC6). So I went through configuration.h and configuration_adv.h but couldn't find the relevant parameter? Anyone know where to find it in the firmware? Anyone changed it yet?