I’m on a Windows XP machine, quad core 2.4 Ghz. Should be fast, right? Wrong!
When I’m running your device or my own Rainstorm sequencer conversion (it’s published here first!) there’s to much MIDI to be sent to the Launchpad. All MIDI is sent nicely, but the pace is lagging behind.
The screen update appeares to be lagging behind when there’s too much MIDI sent to the Launchpad (at least on my machine). I think you’re running into the same problem, for which I have no solution yet.