Asus 66U, dd-wrt. I doubt that's the difference, though. Btw, I jinxed myself. One of the units spontaneously shut off today for several hours until I noticed it (so 800GH for several hours). A software reboot fixed things... but still concerning.
One of my units did the same thing so don't feel bad and at least when yours runs it ran at 1600. It shut down and I didn't notice that one of the chips had been down the whole day until I got home at night.
The same chip that shut down also runs a lot slower than the other chip-sometimes CTA1 (the bad CTA) will report only like 100Ghash until I power cycle it...really have to wonder if there's a bad core or something