I can underclock the RAM down to 725, below that it fails to accept it and the sliders reset. I am talking of when CCC and afterburner report what I set, but GPU-Z and performance figures reflect default. Sometimes the clocks get applied, and then revert at some point, and sometimes the just won't take. Yesterday, I restarted and they were applied, but reverted shortly after, today, about an hour ago, they just decided to be applied without me doing anything. I don't know how long these will stay.
Basically there is a discrepancy between what CCC and afterburner report (under load, 300/300 for idle is fine), and what GPU-Z and performance figures report. Sometimes I can get them to apply, sometimes, they revert for no reason, and sometimes they just won't apply at all.