quick question , which is better for this miner ? GPU core speed or GPU RAM speed ?
Typically with Equihash, overclocking the ram will produce an increased hashrate.
Claymore's ZCash miner:
Overclocking the core clock speed increased hashrate. Overclocking or underclocking the GPU RAM actually decreased hashrate, with overclocking also decreasing GPU stability.
That doesn't make a whole lot of sense to me given that Equihash is a memory hard algorithm. Its possible that increasing the gpu clock might help some, but that's not what's doing the majority of the processing so it should not produce a significant change in hashrate. I'm not sure what your doing, perhaps this depends on the type of card your dealing with, however, the above is my experience with the R9 380X.