Looks like Windows 8 introduces some additional DEFRAG options.
**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
There is little information yet about these options but I assume that they might have to do with the rumored new “protogon” file system and that there is more support for SSD included.