Block 481124 has special meaning on both the Bitcoin and BCash chains this week. For Bitcoin, it will mark the point at which Segwit finally moves to active, bringing with it a capacity increase and the potential for massive off-chain scaling through solutions like Lightning Network. For BCash, it delivered the first increase in mining difficulty since it split from Bitcoin on August 1st. The week also saw the emergence of a new phenomenon on both networks , a back and forth movement of hash power as miners chased profit. To understand the effect of having two high profile SHA-256 based cryptocurrencies we need to look at how the two chains manage mining difficulty. This, along with the price of the coins and the fees brought in from transaction fees, determines how profitable their mining is.