I've been using RMClock with my T60p T7200 since I got it and it works great. Currently using the latest 2.30.1 beta release. Lowering the voltage has a significant impact on heat put out.
As far as the ATI chip is concerned, the only thing you can use (that I know of) is PowerPlay. ATI tray tools for example lets you adjust mem and core speeds, but doesn't allow as drastic throttling as PP does, and also ATT doesn't underclock. If only there was an RMClock utility for the GPU, that would be perfect (performance on demand for GPUs makes a lot of sense). One nice feature of PP however is that you can set up profiles which activate with keystrokes, and since RMClock can be used with command line instructions, I've set it up so that ctrl-shift-1 sets PP to maximum battery and RMClock to my performance on demand profile, and ctrl-shift-2 sets PP to maximum performance and RMC to my max performance profile as well (tpfancontrol taking commands like this would be excellent, so I could set it to my auto settings and fixed at level 7 with the same keystrokes). I'm pretty happy with this configuration, as I can quickly set everything to max performance before playing a game or doing anything intensive, then back to power saving modes with a simple keystroke.
Since a picture is a thousand words, here are some links to screen shots of my configuration.
Mod Edit No inline pics allowed without a warning in the thread subject.
Harryc
http://i120.photobucket.com/albums/o175/jeepcoma/management.jpg
http://i120.photobucket.com/albums/o175/jeepcoma/profiles.jpg
http://i120.photobucket.com/albums/o175/jeepcoma/max.jpg
http://i120.photobucket.com/albums/o175/jeepcoma/pod.jpg
http://i120.photobucket.com/albums/o175/jeepcoma/advcpu.jpg
And for fun I was playing around with some stress testing. You can see that with the fan forced off, with the voltage at .975 after 135 seconds the temperature has reached only 71*C. It eventually stabilized at about 95*C after ~600 seconds, remember this is with no fan, and none of the thermal protection features were activated by the CPU. I then forced it to clock down to 1 ghz and .950V and you can see the immediate drop in temp to hold stead at 85*C.
http://i120.photobucket.com/albums/o175/jeepcoma/nofan1.jpg
http://i120.photobucket.com/albums/o175/jeepcoma/nofan2.jpg
Here's the same test at stock voltage.
http://i120.photobucket.com/albums/o175 ... oltage.jpg