Pete has a 2011 iMac and he needs more screen real estate. What monitor should he get? Leo says that iMac can probably drive more than one screen. Pete says that third party monitors throw off the aspect ratio, but he doesn't want to pay the Apple premium.
Leo says Apple sets a preference pane for each monitor and sets them separately. So Pete can just get a monitor from Dell instead. They have Thunderbolt capable monitors and will cost half as much, and the aspect ratio will be fine.