Results on a 6970:
https://docs.google.com/spreadsheet/ccc?key=0AvQpPCbSGattdEpoNmdwRm1La25EM1BhVk1feWdQYVE&usp=sharingIt seems that there is no real advantage running a thread of scrypt and a thread of SHA256 except perhaps squeaking a few KH/s or a couple MH/s on the edges (presumably by picking up unused cycles when GPU is 99%), however, my methodology is far from perfect...cgminer one window guiminer-scrypt in another... I'd be interested in someone duplicating the results.
You would think that the availability of bandwidth/memory would help in script mining, but it doesn't seem to.
Is there a way to dedicate a number of shaders to one thread and a number to the other? This test only utilized the intensity/gpu usage variable.