Its rarely mentioned by reviewers when they look at a new phone but we all know it happens.
It was something that became quickly obvious was going to be an issue when I first tried Sony's latest high end device, the Xperia Z. The waterproofing that Sony have effected around the device also provides an additional barrier to ridding the device of heat and you'll find hotspots on the device where you'd probably best avoid holding it.
Its far from the worst offender I've come across. That honour goes to the HTC One X, which is just plain unpleasant to hold when doing anything strenuous to its quad core processor. I'm not exaggerating when I say that the One X too hot to hold on many occasions and needed to be set idle (or switched off) on a solid surface made of an appropriate material to act as a heat sink.
It's also a problem on the Galaxy Note 2 - although here the issue generally only surfaces when using GPS. The additional surface area and newer processor probably assist in lowering the overall temperature and its never gets beyond the uncomfortable.
In the quest to fit more and faster technology into slimmer and slimmer devices are manufacturers compromising thermal efficiency?
Its certainly not going to be doing great things for the usable life of these devices running this hot. Just something else for you to consider when next on the market for a new phone.