Looks like Windows 8 introduces some additional DEFRAG options.

- Perform slab consolidation on the specified volumes
- Perform retrim on the specified volumes
- Perform the proper optimization for each media type
...

New Defrag options in Windows 8 « Anything about IT

Cool !

Option	Description	Option Available
Windows 7	Windows 8
/A	Perform analysis on the specified volumes	Yes	Yes
/C	Perform the operation on all volumes	Yes	Yes
/D	Perform traditional defrag (this is the default)	No	Yes
/E	Perform the operation on all volumes except those specified	Yes	Yes
/H	Run the operation at normal priority (default is low)	Yes	Yes
/K	Perform slab consolidation on the specified volumes	No	Yes
/L	Perform retrim on the specified volumes	No	Yes
/M	Run the operation on each volume in parallel in the background	Yes	Yes
/O	Perform the proper optimization for each media type	No	Yes
/T	Track an operation already in progress on the specified volume	Yes	Yes
/U	Print the progress of the operation on the screen	Yes	Yes
/V	Print verbose output containing the fragmentation statistics	Yes	Yes
/X	Perform free space consolidation on the specified volumes	Yes	Yes

Good post Robert