The phone’s surface registered at 133 degrees Fahrenheit during the website’s testing, which was significantly higher than the temperatures reached by the iPhone 6 Plus, HTC One M8, LG G3, and Galaxy Note 4.
The photo from Tweakers.net shows how much hotter HTC’s new phone became than its competitors during the same test. The image shows the rear surface temperature of each phone — which is the area of the phone you would feel against your hand while holding it.
It’s not uncommon for phones to heat up during testing, as 9to5Google points out, but it seems to be excessive with the One M9. There’s been some speculation that the overheating could be caused by the chip that powers the phone, Qualcomm’s Snapdragon 810. Samsung reportedly opted not to use that processor for its Galaxy S6 because of overheating issues.
HTC said it doesn’t “comment on tests on unreleased software” when Business Insider asked for comment.
The HTC One M9 will launch this spring, but HTC hasn’t announced a final date yet.