Nintendo Switch clock speed on USB power

Presumably to conserve battery life, the Nintendo Switch operates at higher GPU and memory clock speeds in docked mode than it does in handheld mode. What about if the Switch is not connected to the dock but is plugged to a high-wattage USB Power Delivery source using the USB-C port? If the power source provides at least as much power as the dock, does the Switch run at dock speeds, or does it remain at handheld speeds and just use the external power to charge the battery?