HTC is hoping that its new flagship smartphone becomes hot, but not like this. A recent GFXBench benchmark test of the HTC One M9 found the device hitting a surface temperature of 132 degrees fahrenheit. Considering that other phones tested ran much cooler, we could deduce that something that was inside the HTC One M9 and not in the HTC One (M8), Apple iPhone 6 Plus, LG G3 and Samsung Galaxy Note 4 was the culprit. And that could be the Qualcomm Snapdragon 810 chipset which powers the HTC One M9, but not any of the other phones.
This would appear to be confirmation that the Snapdragon 810 is still suffering from the overheating issues that worried Samsung and consumers earlier this year. Still, LG said in January that the chip was one of the least overheating processors, and the chip powers the LG G Flex 2 and the upcoming LG G4. Last month, we reported on a test that showed the Snapdragon 810 running cooler than the Snapdragon 801.
While the HTC One M9 got so hot that you could fry an egg on the back of the unit, the other phones recorded much lower temperatures. For example, the Apple iPhone 6 hit 103 degrees fahrenheit and the HTC One (M8) moved the mercury to 102 degrees. At 100 degrees, the Samsung Galaxy Note 4 ran the coolest of all the phones tested. The LG G3 was the second hottest handset reaching a temperature of 108 degrees.
Keep in mind that the version of the HTC One M9 tested was running pre-release software, which could have muddied the results. Another thing to consider is that the Snapdragon 810 powered LG G Flex 2 hasn't had any reported overheating problems.
source: Tweakers (translated) via XDA