FACT: if your unit has less than 15% free space, it will begin to run slow, no matter the size or type of unit.
it has to do with the amount of space the file table takes, which takes space from storage (they're all in the same disk)
as you add data to the disk, you increase the file table size, and you need more cycles to find a free cluster to store data
partitioning gives you a sort of "limitation" to how much space you will chew from one or another, but the total percentages are mantained, so if your data partition is 80% full and your system partition is 50% full, you're still using more than 80% disk, so watch that.
it's not that severe if you partition, but the issue is still there.
so, if you have one file that's going to take 6GB (saying), you better put it in the disk with the best proportion of number of files to size of file.
if you have multiple files that take 1k of space when the file assignation takes 2k (saying), it's very ineficient storage, but if you have multiple big files, each one taking 2k in the assignation table, it's very efficient storage.
if, in addition, you don't change the arrangement of the files too often, that's even more efficient, since the FAT table doesn't change that much.
that's why the average computer user has to clean, defrag or format their systems so often.... because of all the crap they move around without knowing!
