Copied across from the Nuendo Forum:
FWW, did some tests with a VI-only project: with and without auxs and groups. Can’t say I found any appreciable performance differences (at least, as identified by the Steinberg performance meters or the Apple Activity Monitor). Cubase forum seems to indicate otherwise, but has’t been my experience. I did notice however that Cubase 8.5 seems to do a little better with overall CPU load than Neundo 7 for the same project. Possibly newer code.
Otherwise, the ‘threading metering’ is a little odd: all 12 cores seem equally engaged (vs, different cores showing different loads, some with none etc say like Pro Tools), and, when viewing the 24 ‘threads’ the second thread of each CPU shows as doing bugger-all. Re. the CPU readout on Apple activity monitor, this would seem to show that there’s till a lot of Ram and CPU left idle in the background. One solution that works fine is to rewire slave another DAW as host for VIs etc: Ableton Live or Reaper for example. That certainly puts some serious VI grunt into the system.
Anyways, overall I see as just an interesting sideline really. Nuendo in general is very pleasing to work with overall in my experience. BTW, the Rewire implementation is the best I’ve used.