I’m running OSX Mavericks on 2.5Ghz i7 late '11 MBP with 16GB of memory, projects reside on system drive, but it is Crucial m500 512GB with another similar in the place of optical drive for samples. And before you ask, I have already tried moving projects to another drive, it doesn’t make any difference.
Oh yes, I have emails and Safari and other stuff on this machine, being my only one, but they’re not in use when I’m working. I used to have Boot camp and Windows7 64bit running Nuendo, but saving lag was a problem there too.
The project I’m working on now has some 20 audio tracks, sound effects with some processing (VSL Suite for EQ and limiting, Waves Metaflanger, Voxengo Elephant, some Nuendo plugs like distortion) and small VSL orchestra with few strings, woodwinds and horns through VSL MIR Teldex room + East West Play with two Ghostwriter patches. It’s a trailer job, so there’s a Prores Proxy 1080p quicktime running along. The whole thing is less than two minutes with minimal automation so far. This is not a big project at all and right from the start it saved for around 5 seconds every autosave. I tried to move back to 6.07 but it didn’t help.
On the plus side, my Nuendo is stable (also 6.5 seems stable), otherwise responsive and I haven’t had much crashes with it during recent years, so I’m guessing my plugins are good choice. I have no complaints about new features either like new Mixer which seems to annoy so many here. So far I also like new features 6.5 has to offer, especially when it comes to visibility options. But this saving lag bothers me much! Other thing is Elastique pitch shift which still crackles and pops during live preview (just like in 6.07). The latter I can live with, but saving works transparently in so many other demanding programs without any problems that I have hard time believing my setup is too antique to handle Nuendo’s autosave.