There have been a number of threads regarding the performance of Optimus systems while playing 3D extensive programs and games.
Notebooks with Nvidia GPUs (Graphic Processing Unit) may have a feature called Optimus. These systems have in fact two different video solutions, and integrated Intel GPU and a more powerful discreet Nvidia GPU. In Optimus systems to conserve battery power the integrated Intel GPU is the default graphics solutions and will be used on most situations. Dynamically when the system detects programs that require more extensive graphics power, the system should switch the GPU to the discreet Nvidia GPU. For more on what Optimus does please check the following link from Nvidia.
Be sure to check out Nvidia's FAQ on Optimus
For more information on the how to's especially for Dell systems check out this great article.
You may want a bit more control and wish to manually decide what GPU to use. I am including the method that you can go into the Nvidia Control Panel to manually select the Nvidia GPU globally to become the default GPU.
Selecting a Preferred Graphics Processor
Open the NVIDIA Control Panel
* Select Manage 3D Settings
* Under the Global Settings tab, select High-performance NVIDIA processor
* Click Apply
You don't have to select the Nvidia GPU as the default GPU, you can also assign it for your individual games or programs that you feel require the extra power.
Assigning an application or program to the Graphics Processor
* Click on the Program Settings tab
* In 1: Select a program to customize, click on Add
* Browse to the application/game and open the executable file by clicking Open
* In 2: Select the preferred graphics processor for this program, click on the tab and select High Performance NVIDIA processor
* Click on Apply and the settings will be saved
Creating Optimus Settings for a New Program:
This should give you further control on your notebook, choosing when to conserve battery power when the extra GPU strength is not needed and being able to assign the Nvidia GPU when the power is needed.
For you Steam users out there
Games installed via Valve Steam - nVidia OptimusDefault STEAM Executable File Location: for STEAM Applications: The executable file is located in the following directory: C:\Program Files (X86)\Steam\Steamapps Games will be located in either Common or the account name folder. Special Instructions for Games Installed via Steam: Once you have installed your Steam game, create a shortcut from your Steam games list. Once the shortcut appears on the desktop, follow the instructions below. Viewing Existing Optimus Settings for a Specific Program: