If this latest Sony rumor is true, then it's entirely possible the rumored heat issues with the Snapdragon 810 from Qualcomm were true after all. Supposedly, Sony is struggling with reducing the heat generated by the Snapdragon 810 on their new Xperia Z4 smartphone.
The report indicates that the Xperia Z4 tablet, which also has the Snapdragon 810 doesn't have the same problem, because it has a larger area to spread out the heat. Additionally, the other problem is that Sony's next flagship smartphone is extra thin, which makes it tougher for them to dissipate heat properly with the device.
For now this is just rumor, but it does make you wonder what took Sony so long to announced their next Xperia Z smartphone...
Source: PhoneArena