For WarpView, Elwood on french amiga-ng.org forum gave me the solution with Prefs/Screens (Cha05e90 you were right)
http://www.amiga-ng.org/viewtopic.php?t ... 0&start=18
The solution of Elwood is :
-to open WarpView (WarpView goes on the Radeon9250)
-to switch on the 9250
-to come back on the Workbench (on HD6670) with Amiga-N
-to open Prefs/Screens
-to insert an open Screen
-to customize it with the HD6670
-to save and switch back to WarpView to close it
-at WarpView restart it opens well on my HD6670.
And it's really better than on the 9250
http://zzd10h.amiga-ng.org/Divers/Screens_en.jpg
Nevertheless, for Hurricane, it doesn't work. Hurricane, in full screen mode, doesn't react to Amiga-N.
And even in window mode, when I go out of the Hurricane window and that I use Workbench, in few seconds, my system freezes but Hurricane is still running in his window (I tried with the new and the old Warp3D libraries) .
It's certainly for that that the Amiga-N doesn't work in full-screen mode.
Therefore, you must be right, Hans, not a Warp3D problem.
Thank you all, (and thank to Elwood to learn me how to use Screens pref)