EE Times reported that the problems may have started in the graphics chip. Microsoft designed the chip in-house to cut out the traditional ASIC vendor with the goal of hoping to save money in ASIC design costs. After the multiple product failures, Microsoft went back to an ASIC vendor and had the chip redesigned so it would dissipate less energy into heat.
One possible cause of the General Hardware Error is cold soldering. The added mass of the CSP chips (including the GPU and CPU) absorb the heat flow that allows proper soldering of the lead-free solders on the motherboard, so the solder therefore never has properly melted underneath these chips, which can lead to voids (air bubbles) and weak spots in the solders. Because of prolonged constant temperature changes inside the console, the voids cause cracking. Some people claim this issue does not exist, and claim it is caused by a confusion over this issue. They have suggested that the dull appearance only suggests that the joints are cold soldered, as lead-free solders, even when properly soldered, take on a dull appearance that non-professionals might mistake for a cold solder joint (as the older lead/tin solder solder-joints became dull when not heated sufficiently). This suggestion is, however, rejected by the majority of experts. Lead-free solders also require a greater amount of heat (213 degrees celsius) to solder properly when compared to older lead/tin solders (185 degrees celsius) which compounds the problem.