All About Nvidia Optimus

Switchable graphics, GPU, Cuda

In 2007, NVIDIA developed a new technology for Notebooks known as Switchable Graphics, which allowed the user  to use Discrete GPU (Graphics Processing Unit) for running higher graphical applications and switch to IGP (Integrated Graphics Processor) for running lower graphical applications in order to conserve the battery life. Each and every time a user wants to switch between the Intel IGP and the discrete GPU, the user has to manually change a setting from the NVIDIA Control panel/NVIDIA Switchable Graphics Applet. This Control panel presents a simple menu for the user to select which graphics core should be used to run an application. After the selection of the preferred Graphics Processor, the SBIOS (System BIOS) exposes an interface which enables or disables the GPU.

The Switchable Graphics provided a dramatic increase in the battery life of Notebook’s but it had some disadvantages also which included Screen flicker, Manual Mode Changes, Transition Time, Increased Cost (due to the use of multiplexers as a hardware to render the display) and Blocking Applications.

To overcome the disadvantages faced by the Switchable Graphics, NVIDIA developed a new technology named “Nvidia Optimus”. Optimus didn’t require any manual changes to switch between the two graphical cores i.e. the IGP and the discrete GPU. It automatically selects the best graphics processor to run an application. It delivers great battery life and great performance. In the case of Optimus, the IGP is used only as a simple display controller for flicker free experience with no reboot required. Each and every time a user switches from less critical application to higher graphical application, the Optimus automatically enables to GPU and vice versa. No additional steps are required to switch between the IGP and the discrete GPU. Optimus uses a combination of software and hardware to deliver great battery life and performance automatically and seamlessly.

Optimus includes a unique feature in its software which has Profiled Applications. The applications are profiled based on whether the GPU can add performance, quality and functionality. Optimus does not allow the powering up of GPU unless and until it is necessary. Optimus also allows the end user to customize existing profiles from the list and add new application profiles to the list. If the Optimus does not contain profile of any specific application, a series of verification and validation processes is done by the NVIDIA for that application to determine whether the GPU should be used to display the content or the IGP.

The main benefit of Optimus is that it is completely automatic allowing the user to experience great performance without sacrificing the battery life. However, it has some disadvantages which include Low latency. Optimus does not recognize all applications/games. In the case of Optimus, the IGP can’t be disabled and currently Optimus only supports Windows 7 which is a major drawback.