I just updated my linux computer from 64-bit ubuntu 10.04 to 64-bit ubuntu 12.04. On that bar along the top of the screen in 10.04 are 8 little icons that display the current speed of each of the 8 cores in my CPU (AMD FX-8150). And I can right-click on them and change various settings, like the current core-speed policy for each core. Another applet displays 6 similar-style icons that display the current temperature of GPU, CPU, motherboard, HDDs, etc. These applets are just fantastic!
Now that I'm running 64-bit ubuntu 12.04, I'm trying to get my desktop set up again, and I have been very unsuccessful at installing or replacing these applets. I installed the lm-sensors and psensor packages and a few other packages, but typically they just display some large conventional window on the desktop and don't have anywhere near the functionality (and generally don't show all the devices). I searched, downloaded, installed and tested just about every applet I could find that has anything to do with CPU-core speed and temperatures, but everything is lame, lame, lame in comparison.
I also downloaded and installed the gnome "CPU frequency scaling monitor" applet and the gnome "hardware sensors applet". But they don't appear to do anything when I run them (nothing appears). If I'm not mistaken, these are the two applets that run on my 10.04 system.
What's the solution? How can I get those applets to work with 64-bit ubuntu 12.04 ???
Later: A partial answer, but not nearly as convenient as adding applets to ubuntu 12.04 itself. Execute gnome-panel, remove the top-panel (or move it to the right side of the desktop and make it autohide), add applets to bottom panel (found cpu-core frequency applet, but not temperature applet yet). The basic process of adding the gnome-panel is at this askubuntu link.
However, that answer is missing some important details. First, you can't do much of anything with the existing gnome panels unless you hold down the ALT and SUPER key before you right-click the panel you want to remove, configure, add-applets-to, etc. When you add-applets, you must add 8 of the cpu-frequency applets to display the speed of all 8 cores (or as many applets as you have cores). After you install as many cpu-core-frequency applets as you have cores in your CPU, you need to right-click each one, then select preferences and specify which core each icon provides information for. Otherwise you'll have 8 icons all showing the speed of CPU #0 — not very useful! I found it more-or-less necessary to make the gnome panels auto-hide (and be mostly transparent and approximately the same color as the desktop).
Then "gnome-panel" must be added to startup applications to make it appear whenever the computer is started. The gnome-panel settings and whatever applets were added to the panel will be remembered and restarted by the gnome-panel application.
Anyone who can make these applets work on unity without this hack, please let us know!