Problems with average audio processing load

Currently the indicator of the average audio processing load often jumps into the red.
I have Cubase 8 Pro, version 8.0.40.

If I use some virtual instruments the problems get worse and playing is even stopping for a moment. This didn’t happen earlier, with the same virtual instruments used.


Increase Buffer Size of your Audio Device, please.

Thanks for the advice. I’ve finally tried it and it looks like it has worked.
I’m a bit late with my reply, because I’ve worked on a few pieces without VST instruments.
Now I’m working on a piano-piece with a VST piano.