The Switch doesn't overheat because the chipset is downclocked to reduce heat. If it was running at full power, well..
Some Switches even bent due to the heat produced by a downclocked chipset, one could only imagine what would happen to the Switch if it was running as fast as the Shield.
Some Switches even bent due to the heat produced by a downclocked chipset, one could only imagine what would happen to the Switch if it was running as fast as the Shield.