I decided to try jessie to get PCIe 3.0 with a recent nvidia driver, thus upgrading from wheezy.
(the latter is also the version at which the molecular dynamics code was compiled, and used without calling the X-server)
Following aptitude update
a number of dependecies related to gnome were not met (evolution-common lbfolks25 gnome-panel gnome-shell gnome-theme-extras gnome-theme-standard libreoffice-evolution). This notwithstanding, I decided to upgrade.
After rebooting to get linux matching with nvidia:
the nvidia kernel module has version 304.108 but the nvidia driver component has version 319.60.
Driver 319.6 is just what I wanted. Now, how best fix the problems? Install linux image 3.2?
In the past I tried dist-upgrade, getting into devastating problems.