Sorry if this is a bit obvious but I have done the following for my 4870...
I am using Vista 64 and so need to use
readydriverplus
http://citadel.x10hosting.com/readydriverplus/
This simulates at boot up the pressing of F8 and using the unsigned driver option without any user intervention. Without this applied to Vista 64 it will not work as Vista complains about ATI Tray Tool.
This allows me to run the latest beta of Ati Tray Tools (which supports the 4x70 cards)
http://forums.guru3d.com/showthread.php?t=270486
then I apply the following settings (you can, of course, apply overclocking settings as well if you wish, but I have not tried that)...
this then means that the above dynamic fan / temp combo applies with my card...
Sorry if the above is not useful but it seems fine to me
EDIT: For me the only issue that I have noted is that I have prevented the ATI CCC placing an icon in the system tray as that seems to prevent the ATI tray tool from loading on Windows start up. Otherwise the above works well.