Audio Dropout when playing rendered audio tracks from softsynths

I have what appears to be the weirdest problem.
 
I created a template with two softsynths (Geist and Sampletank 2.5).  Each synth has 16 separate audio output tracks.  All is well when my recorded midi tracks play through the synths.  When I bounce to tracks, all seems well until I go to play the tracks back.  My system plays back the audio very sluggishly before quickly coming to a halt.
 
I'm confused because I thought bouncing to tracks is supposed to free up resources.  My system runs smooth as heck with the synths, but as soon as I bounce each output to an individual audio track and play it back, my system freezes.
 
The audio tracks looks fine.  Sounds okay before dropping out (although I can see my system struggling).  Am I possibly bouncing incorrectly?
 
I have a Windows 7, 64bit, i7 machine that I run Sonar X3 Producer on.  Plenty of RAM.
 
Any suggestions?

Or archive the parts?

All you need to do is raise your sound card ASIO buffers or WDM slider. 
 
Bouncing doesn't get rid of the synth that was bounced. So now you're adding one more track to your project. You must archive and/or freeze the synth to get rid of the synths resources.
 
Cj

Maybe I'm confused.  When I use the freeze function, Sonar bounces the synth tracks to audio tracks and freezes the synth.  Which is exactly what I wanted.  The problem was, when I played back that audio, I would get an audio dropout and my system stalls.
 
Anyway, turns out the "fast freeze" function was the culprit!  I still don't understand how rendered audio tracks would cause my system to stall, but as long as I don't "fast freeze", everything runs smooth.
 
Thanks all!!!!