Ah, if you’re using the VST2 one and it gives trouble, try the VST3.
Point being, it’s possible where one misbehaves the other might not.
Yes, my understanding is that VST3 has some features that can help optimize cpu and memory management. It has a lot of extra parameters for monitoring (info streams plugins can use to make smarter decisions, update the UI, etc.) and control (Note Expression as an example), better controller resolutions, etc. (of course not all players and instruments use them yet). I think it has better support for things like side-chaining, DAW routing, etc (again, all hosts and instruments won’t take advantage of everything).
Since Steinberg controls VST…Cubase/HALion is going to be the first to implement VST3 stuff, while Nuendo and the 3rd party hosts/instruments, naturally, will take a little longer.
Sometimes it takes the third parties a version or two to get VST3 working like it should, and they tend to hold back a bit on Nuendo to implement the ‘bleeding edge technologies’ for the sake of research and bug fixes on Cubase. (Misunderstandings, or general developer learning curve over how the protocol should work for instance, where theory and real world application clash, etc.)