I’ve been trying to find out more about the Nexus 4’s overheating problem for the past few days, and just recently noticed that the Nexus 7 charger might have been part of my problem, at least as it relates to battery heat. However, it turns out that the Nexus 4’s processor also has a tendency to overheat, and that actually causes the device to throttle itself in order to avoid damage.
This behavior makes a lot of sense, as you obviously don’t want to overheat your phone to the point of physical damage, but it isn’t great if you want to make the most of the processor in the Nexus 4. As a result, a curious XDA member actually decided to do some great research and find out why the Nexus 4 would overheat and decline in performance.
In looking at the iFixit teardown pictured above, the user noticed that the Nexus 4’s mainboard should be able to use the entire metal frame of the device as a heatsink. Instead, however, the thermal contact between the mainboard, SOC, and metal frame is neither direct nor very good. The SOC doesn’t make direct contact with the metal frame, which causes the mainboard to channel heat to the battery, also activating the device’s heat sensor in the process.
In short, this poor distribution of the SOC’s heat is a big part of what is causing many of the overheating and throttling complaints about the Nexus 4. The solution, though, is fairly simple once you have disassembled the Nexus 4. Because the SOC should make contact with the frame for ideal heat distribution, there is solid metal below where the processor sits. The only reason there is a problem is that the mainboard is mounted in such a way that there is a small gap between the SOC and the frame that could potentially act as a heatsink.
The fix, then, is as simple as finding a way to transfer the heat from the SOC to the metal frame and allow it to dissipate. The XDA poster tried using thermal paste, which anyone who has ever installed a CPU on a computer will be familiar with, but the gap was too large. Instead, the user made a 0.5mm copper heatsink to connect the SOC with the frame, and provides data to suggest that this solution solved the problem.
I don’t know that I really want to disassemble my Nexus 4, but if the overheating gets much worse, then I’ll probably have to at least give some sort of pieced together heat sink a try. If you’re interested in the modification, the original XDA post has a little bit more information on how to make a heatsink. If I do end up deciding to modify my Nexus 4, I’ll also take as many pictures as possible to compile a more detailed guide.[xda-developers]