Dynamic switchable graphics was designed by AMD in order to increase notebook battery life and it seamlessly swaps between the integrated GPU and the discrete graphics card installed inside the system based on the applications run.
The decision regarding which GPU needs to be used for a specific task appears to be taken by the AMD Catalyst driver, but users can also customize these settings to create their own custom list of applications that require discrete graphics.
At the hardware level, the technology works by allowing the dedicated GPU (dGPU) to enter into an advanced energy saving mode, which has a power draw of around 150mw.
When a graphics heavy task is detected by the Catalyst Control Center, the dGPU is taken out of the power saving mode and used for rendering the images.
These are pushed to the screen via the display engine of the iGPU using a technique called CrossDisplay by AMD. The switch is almost instantaneous and adds just 150ms to the application start process.
From AMD's product page for the technology, we know that this is currently supported by the Radeon HD 6300M and HD 6400M graphics card series and that it requires either an AMD “A” series APU or an Intel processor.
Right now, we don't know which manufacturers have opted for using AMD's dynamic switchable graphics technology in their notebook and which models currently support it.
On the other hand, Nvidia's Optimus, that was introduced back in 2010, is used by a wide variety of laptops from all the major computer manufacturers.
AMD Starts Promoting Optimus-Like Dynamic Switchable Graphics Technology