I got my 4870 to 480core and 1065 memory, the memory OC kept going but I stopped the Auto-Tune out of fear. This is with the CCC btw. Got the fan set to 45% using the profile edit, id idles around 55c-60c, hits mid 70s under load. Better than the 72c idle with no OC and the stock fan speed.
Like somebody else said above, I really dont think its safe to go outside the clocks that the CCC can do right now with the fan speed issue. You can always do the profile edit, but ive actualy had an instance where it failed to load on windows start.