If you check the "convert higher bit rate songs to 128kbps AAC files" box in iTunes

[jamesryanbell]

Does that convert the files and store an extra copy on your hard drive before it transfers it to your iPad/iPhone? ...or does it just convert the songs on the fly and upload them only to your iPad/iPhone and then delete them from the computer?

How does that work?

 

[TuffLuffJimmy]

On the fly conversion.

 

[jamesryanbell]

Thank you for the quick response! I appreciate that a lot.