Yes, auto GPU is required for the memdiff argument. And I *think* the max allowed difference, for 7xxx cards, is 150. Search the CGMiner thread to verify.
Auto Fan and Auto GPU are two of the main benefits of CGMiner.

I don't like the auto adjustments.
And if the max diff between the clocks is 150, then i dont need this argument cuz i already can set the memclock to 1050 without problems...BUT i want to set it lower.
