CPU drain because of PRV track soloing

I have 16-tracks of MIDI data assigned from Superior Drummer-2 using multiple track output, with a reverb plugin on the snare track. Also have two MIDI tracks assigned to Plugsound VST (bass and organ). If I play all tracks, it plays fine. If I go into PRV and solo the Bass track, after a shorttime of play, it will start to distort. I noticed the CPU meter climbs excessively when I do solo mode. Why would soloing a track affect the processor performance so much?

If I remove Plugsound, I won't have an associated sound source to hear the track. Will the track still play (i.e., without audio)?
 
(NOTE: I can't try this at the moment, so my experimentations will be done later.)
 

Got it. Will try tonight.
 
Ultimately I am also trying to find out if my system just isn't  'enough' anymore. Considering upgrades to Win-7, new PC, Sonar 8, etc. Hate to jump too fast if it is just one CPU-draining plugin.

My followup....this issue has me confused.
 
First off, this also occurs in Console view, not just the PRV view as I originally stated (and I will assume Track view also). I substituted for the Plugsound tracks, the TTS1 and Roland Groovesynth.  Same problem occurs. It is the combination of track soloing that is puzzling.
 
I have Superior Drummer on 16 Synth output tracks. For purposes herein, I will refer to that as Track 1. Then the two Synth tracks: TTS1, Groovesynth; tracks 2 & 3 respectively. 
 
      All 3 tracks together:   CPU running 27-28%, plays fine
    Tracks 1 & 2 soloed:     CPU running 27%, plays fine
    Tracks 1 & 3 soloed:     CPU running 27%, plays fine
    Tracks 2 & 3 soloed:     CPU running 63%, distortion, eventual dropout
    Track  1 only soloed:    CPU running 27%, plays fine
    Track  2 only soloed:    CPU running 61%, distortion, eventual dropout
    Track  3 only soloed:    CPU running 61%, distortion, eventual dropout
 
It just seem odd that all 3 tracks play fine together at around 27% CPU. Solo track 2 and/or track 3, and CPU usage more than doubles.
 
Note also that if I archive Track -1, then I can run Tracks 2 & 3 together at about CPU 15% (plays fine), and individually at CPU 14%.  I am missing something. Or maybe my system just can't cut it anymore.
 
 
   

I don't think soloing saves cpu. Everything is run as usuall but result from audio output is not handled. Something like that.

On my computer I also start getting glitches in audio when cpu pumps around 60-70% in sonar statusbar. So that is normal I would say.

But that it would increase cpu load that much by soloing is surprising.

But after all, it's logical that 16 tracks from Superior drummer takes quite some resources.

Just freeze tracks 1 then, and run it all?

You may want to try using the 32 bit audio engine and see if that helps.