You might try installing the latest updates/drivers/software from CCC, which is of course video card related. I’m sure many of us have this installed on our computers, and in my experience it is a necessary piece of crap, haha. It can control a lot of different things involving desktops, displays, appearance, etc., so it might be fighting with N7 somehow.
For the record, I’m on Win7 64, I’ve got CCC, obviously N7, and I have had no issues with audio dropouts, HOWEVER, I always uncheck “release Asio Driver in background” and have in every version of Nuendo I’ve ever had. Seems like enabling it is a really good way to make a driver angry. haha.
Could this bug also be related to my problems: I don’t have the release ASIO in background setting enabled, but I do get drop-outs from the audio engine.
Today for example I loaded the lexicon vintage plate while playing. The audio drops out while loading the plugin, that has always been that way I think. But when the plugin was loaded the audio engine had crashed (no sound and no meter movement).
Like further up in my other post, at 100% asio load I get these problems all the time.