I upgraded from 12.1 to 12.4 and it gave me a really big performance boost!
The driver however has a general problem with HDMI audio out if you are using that, if your computer goes into sleep/powersave it will lose the audio link and only way to remedy that is by relogging your user.
It's clearly a bug in the driver but I'm trying different ways of solving this right now mainly by disabling all manners of powersaving and sleep for the display/PCI slots.