I noticed the problem 2 weeks ago , I was visiting a friend in berlin installed renoise 2.7 on her computer dual Corelaptop ( deinstalled it afterwards ), installed my edirola ua 25 drivers and started playing from midi keyboard .
Renoise was playing back 15 audio tracks , 2 vst’s ( sq 8 -l and tyrell )
i recorded a verry simple bassline for several patterns ( to keep the human feel ) , renoise started lagging after a few patters ,not verry cpu intensive , at that moment I thought it was midi related ( I posted this on the forum ) , now it seems that the problem is also present when recorded from computer keyboard .
The problem could easily be fixed if we could make this new feature optional ( one step record undo ),
https://forum.renoise.com/t/slow-down-gui-response-when-receiving-lots-of-midi-data/32472