I'm looking at my stats on ckpool for an underclocked s7 at 2.86 Th/s. It has been running about 12 hours and I wanted to know if my invalids are reasonable. It says stale: 28,290/10 ; duplicate: 2,829/1. For a total invalid rate of 0.206%. I think this is reasonable but if anyone can confirm I would appreciate it. The overall pool rate for invalids is higher.
Well...my S7s at Labrador (three of them) run all the way from 0.08 to 0.22 on invalids; the older S7 (a two-fan) does better for what reason I don't know. They're all set the same. I've seen many comments on how S7s can vary wildly in performance from box to box. Some of this depends on your Internet connection as well, though. Dunno why you're underclocking; I just run mine at stock, and they're fine...but they're in a controlled environment. When I had them at home they were very sensitive to heat. Never did underclock, though. Just ran enough fans to resurrect the Hindenburg...

Mine on...