Re: limits of ZEC mining

CM 8.0 getting 187Sol/s on 480 4GB (7Gbps), and 176 on 470 4GB (7Gbps), Stock clocks, so it seems 173 is not the theoretical limit.

Correct. See my Nov 20 post about data written to half a cache line. That puts the theoretical limit up around 200 for a OpenCL implementation, with the 1250Mhz core clock being the limiting factor rather (described in my Nov 22 post).

My Sapphires can go upto 1406 and 2250. Will that make any difference?

The 480 8G does close to 200 with 1300 and 2000. Some report as high as 215-220, but I don't like to push core/memory too much, want cards to last a long while, so I just undervolt, and change memory straps. Memory straps less of a boost the more optimized miner is it seems. I have mostly 470s though, doing 175-185.