Fast Bounce Vs Other bounce options

I have been an user of Cakewalk for over 10 years and I must admit, I have never experimented with the bounce options. I usually just use the Fast Bounce option for everything. However, I recently mixed a song down with the Fast bounce option unchecked and, I may be mistaken but, there was an audible difference in sound quality. The mix sounded more open and lively. 
 
Please let me know if my ears were deceiving me.
 
How do you mix down your projects?
 
Thanks, 

tried some times to see if there's a difference, but fast/nonfast were really the same (nulled).
iic checking '64 double precision' doubles the size of the files, so I have that unchecked always, and I never dither...but all these things don't make or brake things imo.
 

Thanks for the feedback folks. I'll continue to play around with it.

Within SONAR, there is no difference. Think of a slow bounce as a slowed-down fast bounce. Slowed so you can listen to it if you wish. Other than that, the math being performed under the hood is the same.
 
Of course, there are rare exceptions. For example, if you are low on RAM and have a slow disk drive that cannot keep up with streaming samples, you could end up with crackles or dropouts in the bounced audio that can be fixed with a slow bounce. But if you bounce a project and hear no artifacts, you can rest assured that you haven't sacrificed any quality by performing a fast bounce.
 

the brain has its ways of playing games with us.
this is one of them.

I can't find this information in online help so I'm not sure if it's true, but the post #9 in the thread below says that plugin upsampling only works when doing a non-real-time bounce. So, if the information is true and if your project is recorded at 44.1kHz/48kHz, fast bounce should probably make the project sound more 'open and lively' (if plugins that benefit from the upsampling feature are used in the project). 
http://forum.cakewalk.com/The-Foxboro-PlugIn-Upsampling-Thread-m3247497.aspx
 

Bouncing is definitely a mysterious thing in Sonar.  I spent a lot of time trying to figure out differences, why and how --- dramatic changes can occur from the "Source Category" choice and from the "Source Hardware Outputs" choice.   The 64-bit engine setting also may be an issue (I always leave it checked).  
 
Another big reason that changes can occur has to do with controller lookback -- if you are attempting to bounce just a section of a project, there's a strong likelihood that your mix will be quite different than if you bounce the whole thing. 
 
Another thing that popped out of previous discussions had nothing to do with Sonar -- if you change the bit depth (accidentally or intentionally), that can change the sound too.   Probably obvious to many, but it caught me when using a default "save-as" that had 16bit set -- this was in SoundForge, working with audio from the Sonar bounces.
 
There was at least one long thread about this, maybe 6 months ago.  Probably many threads over the years. 
 

icontakt
I can't find this information in online help so I'm not sure if it's true, but the post #9 in the thread below says that plugin upsampling only works when doing a non-real-time bounce. So, if the information is true and if your project is recorded at 44.1kHz/48kHz, fast bounce should probably make the project sound more 'open and lively' (if plugins that benefit from the upsampling feature are used in the project). 
http://forum.cakewalk.com/The-Foxboro-PlugIn-Upsampling-Thread-m3247497.aspx

Good find. I'd missed that post.
 
I'm wondering if Craig mis-spoke, though, and meant to say the oversampling is disabled during an audible bounce. There'd be no need to avoid the overhead for a slow bounce unless you're simultaneously playing back the mix while bouncing.