Based on the information provided the gen4 is coming along according to schedule. There will be some time span in which it will be evaluated. However, to put things in perspective any new chips will not move the profit margins too much. Profit margins are mainly a function of BTC price, network power and average upkeep costs. The tech has moved quickly in the last 2 years and is hitting Moore's barrier pretty hard. Main profits will likely come from innovative ways to reduce capex and opex, which not necessarily requires the latest chips.