I’m also suffering from slow saves since upgrading to N6.5.
It affects all saves, both auto-saves and straight command-S saves. The whole system beach balls for 50 seconds (no joke, i put a stopwatch on it) before working again. This is on a project with just 49 tracks inc groups and fx. The first time auto-save kicked in it looked just like a crash and I nearly did a force-quit.
In all previous versions of Nuendo a command-S save was near-instantaneous for me.
Please fix. Right now I’ve had to turn auto-save off completely which worries me.
Oh, this is N6.5 on a 12-core 2010 Mac Pro running 10.9.4