This is the worst logic I've ever seen. The article is complete nonsense. Also, it is 95% guaranteed the 840M-860M is maxwell architecture on 28nm. You don't need to read some moron's article to think otherwise. Higher end maxwell cards are coming this summer with 20nm processing
The 2014 (or early 2015) 15" rMBP will either have the 850M (maxwell) with 30-35W TDP (much cooler, and much better efficiency) with a moderate performance increase. Or it'll have the 860M 40-45W TDP with huge performance increase, and still cooler then the current 750M.
Maxwell lowered TDP (power efficiency) by tremendous amounts. Right now the 750M has eh performance and runs at 45W TDP