Note that if you do a fsck, you'll generally see what appears to be a LOT of fragmentation on the empeg filesystem - eg, sometimes around 50%. This is nothing to worry about, it just means that 50% of the files have at least one fragment (ie, are not contiguous).
Seeing as, unlike normal FSes, the empeg's data partition consists exactly 50/50 of (a) HUGE files, of 3+MB each and (b) Teensy files, of <1k each, this is expected behaviour and won't affect the performance of your system.
Statistics lie :)
Hugo