Well,
After a long time with this probleme I can say it could be because my disk is
an xfs drive, according to this there is a problem since 2005 !!!
http://bugzilla.gnome.org/show_bug.cgi?id=363400
** Summary changed:
- Slow file transfert with mounted disks (fat32 or ntfs-3g etc..)
+ Slow fil
*** This bug is a duplicate of bug 58672 ***
Thanks for the bug report. This particular bug has already been
reported into our bug tracking system, but please feel free to report
any further bugs which you find.
** Changed in: nautilus (Ubuntu)
Importance: Undecided => Low
Assignee: (unas