[xbs08]

I made a backup of .xbmc, format to F2FS, restored .xbmc and reboot.
You'll need GParted 0.16 or up to format to F2FS.

BTW copying .xbmc folder to EXT4 took a lot longer than it did to F2FS

F2FS - Patriot USB 3.0 16 GB - 151MB Thumbnails

Code:

OpenELEC:~ # time sh -c "cp -r /storage/.xbmc/userdata/Thumbnails/* /storage/downloads/Thumbnails && sync"
real    0m 27.48s
user    0m 0.21s
sys     0m 4.01s

OpenELEC:~ # time sh -c "cp -r /storage/.xbmc/userdata/Thumbnails/* /storage/downloads/Thumbnails && sync"
real    0m 27.49s
user    0m 0.16s
sys     0m 4.01s

OpenELEC:~ # time sh -c "cp -r /storage/.xbmc/userdata/Thumbnails/* /storage/downloads/Thumbnails && sync"
real    0m 27.84s
user    0m 0.21s
sys     0m 3.96s

If you can, please do the same tests so we can compare results.
Thanks.