How can I move Logic files to an external drive to save space?

I believe I simply moves the files from the Apple Loops folder and then drag these to the Loop Browser to get Logic to recognise the new locations. But, when I go to Apple Loops in /Library/Audio/ Appleloops, the file only containss 3.51Gb. Surely there should be more than that? I have downloaded all the additional content so I am puzzled. Can someone help please/

Thanks