OK there are a number of reasons for the split partitions
Number one, the first partition will sit on the outside of the disk, therefore copying and moving files will be quicker I.E his video files
His smaller files I.E PDF files, Will sit further inside the platter which means it's a slower part of the disk.
That's the reason for 2 partitions, it splits out the larger files from the smaller files and puts them on faster or slower parts of the disk.
If that still...