Based on Nintendo's statements, I'm pretty sure all the chips will be in the Switch itself (this is how I have decided to refer to the tablet unit thing). The rumors I've heard put the Switch screen at somewhere between 720p and 900p (HD and HD+), so I suspect that when the Switch is being used in portable mode, it will run in a lower power mode and render at a lower internal resolution. Once it is docked, it will switch the internal rendering resolution to full, and draw as much power as it wants from the line.