Problem reproduced. I run folding GPU at stock speeds, launch Afterburner for the first time since boot, tweak clocks to 770 core, half an hour later, I check, it's still running at 770MHz. Then I stop folding on the GPU, wait for the clocks to drop to 405MHz, memory speed doesn't change, I start it again, the clocks don't ramp up - they stay at 405MHz. Then I stop the folding client again, this time the memory drops down to 162MHz from 850MHz, and I start the folding client again, the clocks don't come up.
Mothership: Thuban 1055T@3.7GHz, 12GB DDR3, M5A99X EVO, GTX470+Icy Vision Rev.2@840/3800, Vertex 2E 60GB
Supply ship: Sargas@2.8GHz, 12GB DDR3, M4A88TD-V EVO/USB3
Corsair: Macbook Air Ivy Bridge