Cubase 7 and vst synths problems

Cubase
1

Hello I have a strange issue with cubase 7 and plugs like nexus or kontakt

If I load up 5 or more instances of the same plug playing rough the same midi notes.
Some of the tracks don’t play any sound. If I solo them they come back to life.

I have win7 16gb rme fire face and intel 9380k CPU so no power problem.

What could it be?

2

It sounds like the polyphony of the plugin is being maxed out. You may have too many notes playing at once.

3

I didn’t know Cubase had a polyphony.

I’m using different inst tracks. How is it possible the Polyphony is maxed out? There are tracks not playing at all.