Been struggling with this issue for a while, and seem to have found a solution-ish. I’ll write everything I experimented with so hopefully bits of it might help others who are getting the problem.
So I work in projects sometimes over 1000 tracks with a lot of audio/MIDI/instrument and FX tracks, and the rubber band thing (which occurred during moving items, using the scissors, re-sizing, drawing a selection box and a lot more), was there whether I had a 1500 track project open, or a blank project with a single MIDI track…
I can confirm it has nothing to do with the power or specs of your PC. I had this issue on my old one, and the new one which I got recently, with the fastest i7 CPU, full of RAM, clean install of windows blah blah.
At first, I thought there was an issue because I would get the lag more on my 4k monitor, than if I dragged the project to the other 1080p screens… so I got a good GPU… no luck. It was a bit faster, but the main problem was still there… hence, GPU will not fix the issue.
In the end, I found the 8.0.0 version of Cubase saved on a hard drive. I uninstalled the version I had (not sure which update it was… the latest I think)… installed 8.0.0, and voila, the problem has disappeared, completely, for projects of all sizes. If you can, it might be a good idea to try and put the original version 8 back in and see if this solves it for you too, I’d be very curious to know if the problem is in one of the updates! I can’t remember if there are any really important features of any of the updates which might stop people downgrading back to the original version?
Anyway, hope it helps.