system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is a CPU so small?

Like I understand that it has to fit on the motherboard and socket size but why that specific size?
gpt
Smaller chips - > shorter circuits-> faster signal transduction and less resistance - > less heating and less voltage needed (goes hand in hand). 

Heating is the biggest problem for the chip and one of the limiting ones for more power.