as i tried it on various computers with various OSes, there are several window managers - on linux machines gnome and lxde. no difference.
graphic card: on notebooks all kinds of more or less crappy integrated gcs (ie. intel 945gme, ati hd4200), on pc i have some basic nvidia (standalone, ie. not-integrated). again, no difference.
as i mentioned before, the problem is not present with old (pre-lua) versions of renoise.
to make the research complete, i’ve tried renoise and akai mpk mini on an imac (with osx tiger). although the mixer faders react somewhat more fluently than on linux and win, there is still some random latency, depending on the speed of knob twisting and number of controllers being operated at the same time (faster movements, more knobs = larger latencies). again, plugin sliders react flawlessly.
could you please check if things work better in the latest 2.7 Beta (B5)?
I’ve tested this with a “mpk mini” here, and the only thing I noticed is that on very slow computers, some mappings may react slowly. We’ve tweaked this in the latest beta a bit.