The chopiness is directly related to how fast your processor is and what fx or pan/crop edits you are doing/applying (and what the file type is of the video). The chopiness will only be there when you preview it. It will not show up on your final output file.
I don’t know if the consumer versions of Vegas have ram preview, but if it does, depending on the amount of ram you have, you can see a realistic preview for a selection on the timeline that is tied to the amount of ram you have- look for RAM preview in the help file for your version of Vegas.
j razz