Hello, Running only firefox, htop indicates: an occupation of 14.6 of the memory and of 11.5% for gnome-shell (actually 1.4 G/ 3G of RAM). This slows down the machine without clear explanation. Actually, it becomes a lot worst as soon as I run xmgrace for example. I run fc21 Of course, if I kill firefox, the memory occupation is gone, but I still keep the 11.5% of gnome-shell while only one gnome-terminal is open. (I do not run ant thing, only the OS runs some stuff). 2468 pdupre 20 0 2113872 351616 58956 S 3.3 11.5 7:20.44 gnome-shell 3205 pdupre 20 0 1655876 436136 95340 S 2.0 14.3 19:28.00 firefox kiB Mem : 3054792 total, 214252 free, 1071044 used, 1769496 buff/cache Thank for nay help. =========================================================================== Patrick DUPRÉ | | email: pdupre(a)gmx.com Laboratoire de Physico-Chimie de l'Atmosphère | | Université du Littoral-Côte d'Opale | | Tel. (33)-(0)3 28 23 76 12 | | Fax: 03 28 65 82 44 189A, avenue Maurice Schumann | | 59140 Dunkerque, France ===========================================================================