gnome-shell-extension-freon
Freon is forked from gnome-shell-extension-sensors. Freon is an extension for displaying CPU temperature, disk temperature, video card temperature (NVIDIA/Catalyst/Bumblebee&NVIDIA), voltage and fan RPM in GNOME Shell.
More info in wiki
Installation from git
git clone https://github.com/UshakovVasilii/gnome-shell-extension-freon.git
cd gnome-shell-extension-freon
mkdir -p ~/.local/share/gnome-shell/extensions
cp -r freon@UshakovVasilii_Github.yahoo.com ~/.local/share/gnome-shell/extensions/.
restart GNOME Shell (Alt+F2, r, Enter) and enable the extension through gnome-tweak-tool.