NVIDIA Optimus technology is a seamless technology designed to get the best performance from the graphics system while allowing longer battery, without having to manually change settings. Thus when an application is run that requires extra performance or graphics quality, then the system will run the discrete GPU (dGPU); when the system does not require such enhanced performance it will let the integrated (iGPU) to handle.
Most notebook computers come with either a discrete (dGPU) or integrated (iGPU) graphics solution.
Discrete graphics solutions feature a dedicated Graphics Processing Unit (GPU) capable of playing games, watching HD video or running GPU-based applications. However computers with discrete graphics tend to be heavy in power consumption and slightly larger in size in order to incorporate the dedicated discrete GPU.
Integrated graphics solutions on the other hand feature memory sharing technology to help save power consumption and allow for longer battery life. However computers with integrated graphics solutions will not usually run games, HD video or GPU based applications without major performance limitations.
HOW OPTIMUS TECHNOLOGY WORKS
When the system is powered up and is displaying just the desktop, the dGPU will be powered off. In this case the system is running in the same way as a system without a discrete graphics solution. However when an application that requires use of the dGPU is run (e.g. games or HD video), the dGPU is powered on and takes over the processing duties. If the program is closed, then the dGPU will be powered down back again until required again.
One of the most important aspects of NVIDIA Optimus technology is that it will switch between the integrated GPU and discrete GPU seamlessly and automatically, and does not require any input from the user. However customization options are available (via NVIDIA Control Panel) for users who prefer to set their own parameters for GPU usage.