They've also had a similar mode on the GPU since the launch day patch, the 768 MHz docked and 307.2 MHz handheld speeds can temporarily boost 25% to 921 MHz and 384 MHz, presumably to avoid dips.
Seems like a very dynamic platform all round, should certainly stand the test of time, can see why they're not rushing to bring out upgraded systems, they essentially choose when mid-cycle is. Lets not forget the GameBoy and DS lines are technically multi-decade systems.