iirc gen3 datacenter will be 1ph once filled with new chips. 3 blocks is nothing compared to what it will be with 1ph.
Is there really only going to be one data center with a total of 1PH? I thought we had a 10% network capacity target? I think you may be confusing friedcat's interview where he expected to have 1ph online by the end of 2013 with Gen2 that fizzled. Even that quote had some contention as there was confusion on the translation...
I would expect much more than 1ph out of Gen3. I've not been following this security for a while so please, correct me if I'm wrong.
In the most recent update from jutarul:
5) What is the status and capacity of the immersion-cooling data center, and will it house some of the 3rd generation hardware used for mining?
re 5) Capacity is at least 1P.
AM also has an air cooled datacenter + franchising. I would guess they end up mining with 5ph.