I have discovered that the OnePlus's processor may not be adequately cooled. Since smartphones are passive devices, they aren't actively cooled by fans like computers are, so they rely on heat dissipation through the use of a heatsink of some sort.The Samsung Galaxy S4's chassis is made of magnesium alloy, just not as abundantly so as the OPO. The logic board well is form-fitting, and there are thermal pads that contact the underside of the logic board to the chassis in order to dissipate heat. Since the chassis is so big, heat is easily dissipated.The OPO, however, looks like it's insulated at the area where the chipset is closest to the chassis with what seems to be carbon paper/film. Now, I'm no materials expert, but I'm pretty sure carbon in this state should act as an insulator.On the underside of the logic board, we see that there's a steel cage covering the on-board components, covered by a thermal pad.What does this mean? It means that under load, a Samsung phone will feel hotter to the touch, because that's the passive cooling system in action. In the case of the OnePlus one, it might not feel as hot as a Samsung under similar loads, but when it does get hot, it's really,hot. So hot that the small heatsink and carbon film can't contain or dissipate it.For size comparison purposes, here's the Galaxy S4's logic board next to the OPO's. Remember that the S4 is a 5 inch phone.Assembly was probably quite sloppy; the tape used to insulate the speaker contacts is off-center on the left speaker.The weak vibrate motor cannot be upgraded, as it is soldered to the flex.The earpiece grille is centered on the front of the phone, but it is offset to the left internally because the camera module takes up the space in the center, as can be seen below. This may or may not contribute to the low earpiece volume, since it is channeled.The rear microphone (pictured below) is also offset slightly lower than the hole next to the rear camera. Outside, the hole is parallel to the center-point of the camera lens, but internally, it is parallel to the top of the flash LED closest to the camera. I'm not sure how effective this placement is. The top microphone (refer to picture above, left of front camera hole) is channeled.Man, this took longer than expected.