Solved Preferences ...

In Preference window what should my dynamic ram be set to? Vegas Pro has worked great ,,, until I used Float and Pop ... now it wants to stutter ..when i had no problem with preview playback with other effects ..

Leave Dynamic RAM Preview exactly where it is at 200MBs - only change this if you plan to create RAM Previews while editing.
This setting does not affect Preview Window performance, but instead is the amount of RAM available for rendering small sample previews that are stored temporarily in your RAM memory.

Example:
Set RAM to say 4 or 6 GB.
Now drag out a loop region of about 5 to 10 seconds around your Float & Pop - drag blank area above Timeline Ruler.
Now press Shift + B
An uncompressed video will now be rendered into RAM.
Press play and it will be smooth.
Resizing the Preview Window or changing the Quality Setting will clear the RAM cache.

It is not unusual to see Animated Text Events lag during playback, once you start adding more layers and tracks to a project.
Setting to Preview Window to Preview (Auto) quality will help improve things.
Also make sure that you have set your Project Properties for the entire project before you begin each project.
Changing things like the Frame Rate after you have added a Text Event, will cause lag.

I have also found that re-booting my computer and then re-loading a project, can help with Preview playback sometimes.

Regards
Derek

Thank you very much Derek!! I appreciate you taking the time first off ,to help novices like me ,and secondly for sharing a wealth of info on this site .. Thank you .. I'm sure I'll have more ..