PS4 and X1 shipped nearly 30 million consoles at the end of 2014 according to AMD

[celador]

Well 500k on the shelves for either console is too low, combined is not even feasible.

Obviously X1 is the culprit for any overtracking. If these numbers are accurate, and the people on gaf who have talked about channel stuffing in the US are correct, X1 may be substantially overtracked.