I would like to ask, is defragment running under safe mode would be better? Just like scanning virus under safe mode, sometimes can get a better result as some system application is not using, hence have possibilities to scan out the virus for these system files. But, is it also the same for defragment hdd under safe mode?

IMHO, it will still be the same. Defragmenting is just reorganising bits and bits of info on the HDD so that the data fetching cycle can be done faster without looking for specific parts for longer cycle, hence access time is shortened.

hurm .. it might helps but you wouldn't notice it actually ... as in safe mode, there are more files released (not being use by other software) for defrag to do its work.

but it is in my logical theory formulation only ... bro experience might be rite oso

there might be a SLIGHT different. yup going to be a bit faster but it'll do just the same.. re-organizing the files in a manner that windows can access the files in a more organized way next time

u can try it and if got any different then share with us..as i know it doesnt show any different defragment under safe mode

It's much better to do defragment in offline mode like from bartpe/boot cd because in online mode some files on hard disk are in use like system files etc which would prevent defragger to move them around

Yes it is because the system files are not utilisted compared to safe mode / normal mode.