At 700MHz they're pretty much tapped out, and overclocking is not an option until we figure out how to control voltage. My OG S7s run at 6TH/s in comparison with overclocking.
I totally agree with you. I'm coming close to making the decision to go ahead and under clock these back to 600 MHz from the 700 MHz factory setting. If I'm not mistaken, the batch 6 (135 chips) were clocked at 600 MHz and hashed at 4.0 TH/s? I'm thinking about treating the new 135 chip rigs as batch 6 and under clock all of them to 600 MHz for longevity.