Processingmeter goes quite high when adding Halion Sonic VST

Need some input on this behaviour, want to know if it is how it should be and the possible reasons why

When I have added a VST-instrument, in this case Halion Sonic (not SE). And then have added midi-tracks mapped to the same VST-instance. And then add, in this case, The Native Intsruments ‘The Giant’ on one instrument track in same project I notice that I get pops and dropouts and that the processing meter is quite high when I just play ‘The Giant’. And when I remove the whole Halion Sonic VST-instance the processing meter is low again.

Is this how it should be and why is the Halion Sonic instance affecting the processing meter, it is not used when I play ‘The Giant’. Is it because it uses the available RAM ? Is there any solution to it?

Forgot to mention: Use Cubase Artist 7.5, have an old Sony Vaio Laptop, Intel Core Duo, 2,4 MHz (something) 4 GB RAM

I meant 2,4 GHz of course…