Till recently there were very few notebooks which came with switchable graphics solutions. They were the right answer to the gamer or power user on the move with the discrete GPU performing when power was needed and the onboard graphics taking over when battery life was essential. However these solutions were not so ideal and in fact were very cumbersome to operate. In most cases the user had to flip a manual switch after shutting down the machine or closing some applications. Thus these switchable solutions never got off to a great start.
Enter nVidia Optimus, the answer to all such woes. Nvidia says the ideal way for a switchable graphics to work is for the GPU to fire up when the user opens a graphics intensive program and then shut down once it is closed. This is exactly what Optimus claims to achieve.
Previously switchable graphics solutions connected the integrated graphics and the GPU in a parallel connection and employed additional multiplexers to allow for the switching. This design was quite a bit complicated and also the end signal quality was poor. Nvidia’s Optimus approaches this problem in a whole new different way. The new architecture sends the frame buffer data from the GPU to the integrated graphics through the PCIe interface. This is then sent to the system memory and from there to the output display unit. This new design does away with the need of extra switches or multiplexers which eat on the space available on the motherboard. This solution raises the question of a time lag but nVidia claims the lag to be less than 3ms operating at a frequency of 60Hz.
There have been modifications on the software side too. This new technology is not compatible with Windows Vista as it allows only one display driver to be working at any time. Windows 7 has native support for multiple display drivers. There also have been changes in the drivers of nVidia. There are application profiles and when one of the applications is launched the GPU is fired up. When not needed the GPU is sent back into a no power state. NVidia has actually given a demo in which they plugged out the GPU from the system then put it back and fired it up, all the while the OS was running. NVidia has also initiated a profile distribution system where the applications can be updated. The user also can fire up the GPU manually or add an application to the list.
The seamless switching over Optimus has enabled much longer battery life without compromising on performance. We cannot exactly explain the design architecture completely but from a user’s viewpoint this simply is an excellent option.