They already get 'confirmation' from xbox insiders that MS also has RAM on Interposer, aka HBM, via patents.
So, Anaconda is going to have an HBM configuration, Lockhart not? Because if Lockhart is reportedly the cheaper system with 12-16GB ram configuration, then HBM is out of the question. Unless the $299 price point is no longer an option.
And let's say for the sake of arguing that both systems are using two different memory architectures. Wouldn't this make development of cross-porting between the systems even more tricker (i.e., bandwidth differences, caching, latency, etc.), considering the rumored gulf in TF performance already between the two platforms?