Oh it is most definitely 99%. Don't let what people claim they do on internet message boards affect your judgement. I've never seen a single human being in the wild carrying an iPhone without a case of some sort. Not since maybe the 5c days.I believe it’s more like 70%, but the hilarious part is cases are a giant insulator so the furthest the heat dissipates is throughout the phone, which the vapor chamber facilitates but the aluminum outer casing not as much. An aluminum mid plane with a titanium outer band with the vapor chamber may very well have performed nearly identically to the aluminum unibody when both encased in rubber and plastic.