GPU switching

GPU switching is a mechanism used on computers with multiple graphic controllers. This mechanism allows the user to maximize the performance of the battery or the battery life by switching between the graphic cards. It’s mostly used on gaming laptops which usually have an integrated graphic device and a discrete video card .

Basic components

Most computers using this feature include integrated graphics processors and dedicated graphics cards.

Integrated graphics

Also known as: Integrated graphics , shared graphics solutions , integrated graphics processors (IGP) or unified memory architecture (UMA). This kind of graphics processors usually have much less processor and share the same memory with the CPU .

Sometimes the graphics processors are integrated onto a motherboard. It is best known as: on-board graphics. [1] A motherboard with on-board graphics processors does not require a discrete graphics card or a CPU with graphics processors to operate.

Dedicated graphics cards

Also known as: discrete graphics cards . Unlike integrated graphics, dedicated graphics cards-have much more processing units and-have icts own RAM with much Higher memory bandwidth.

In Some boxes, a dedicated graphics chip can be integrated onto the motherboards , B150-GP104 for example. Regardless of the fact that the graphics chip is integrated, it is still counted as a dedicated graphics card because the graphics chip is integrated with its own memory.


Northbridge control

Most computers have a motherboard that uses a Southbridge and Northbridge structure. The Northbridge is one of the core logic chipset that handles communications among the CPU , GPU , RAM and the Southbridge. The discrete graphics card is usually installed on the graphics card slot and the integrated graphics is integrated onto the CPU or occasionally onto the Northbridge. The Northbridge is the most responsible for switching between GPUs. The way it works usually has the following process: [2] [3] [4]

  1. The Northbridge receives input from Southbridge through the internal bus .
  2. The Northbridge passes the input to CPU through the front-side bus.
  3. The CPU runs the task assignment application (usually the graphics card driver) to determine which GPU core to use.
  4. The CPU goes down to the Northbridge.
  5. The Northbridge passes the GPU core.
  6. The GPU core processes the process and returns to the Northbridge.
  7. The Northbridge sends the data back to Southbridge.

Southbridge control

The Southbridge is also named as I / O Controller Hub (ICH). It handles all of a computer’s I / O functions, such as receiving the keyboard input and outputting the data onto the screen. The way it usually works with two steps: [5]

  1. Take the user input and pass it down to the Northbridge.
  2. (Optional) Receive the rendered product from the Northbridge and output it.

The reason why the second step can be used is that the output is directly related to the discrete graphics card which is located on the Southbridge.

Main purpose

GPU switching is mostly used for saving energy by switching between graphic cards. The dedicated graphics cards consume much more power than integrated graphics but also provides higher 3D performance, which is needed for a better gaming and CAD experience. Following is a list of the TDPS of the Most Popular CPU with integrated graphics and dedicated graphics cards.

TDP of Integrated Graphics and Dedicated Graphics Cards [6] [7] [8] [9]
Model Platform
Integrated Graphics Dedicated Graphics Cards
Intel TDP Nvidia TDP AMD TDP
CPU Model & Frequency Intel IGP Series
Intel Core i7-6700K @ 4.00 GHz Intel® HD Graphics 530 91W GTX 1080 180W Radeon R9 Fury 275W Desktop
Intel Core i5-6600K @ 3.50 GHz Intel® HD Graphics 530 91W GTX 970 145W Radeon R9 Nano 175W
Intel Core i7-4790K @ 4.40 GHz Intel® HD Graphics 4600 88W GTX 780Ti 250W Radeon RX 480 150W
Intel Core i7-6700HQ @ 2.60 GHz Intel® HD Graphics 530 45W GTX 1080 165W Radeon R9 M485X 125W Laptop
Intel Core i7-6500U @ 2.50 GHz Intel® HD Graphics 520 15W GTX 980M 100W Radeon R9 M470X 75W
Intel Core i5-6200U @ 2.30 GHz Intel® HD Graphics 520 15W GTX 880M 103W Radeon R9 M470 75W
Intel Core i5-5200U @ 2.20 GHz Intel® HD Graphics 5500 15W GTX 870M 103W Radeon HD 7950M 50W

The dedicated graphics cards exhibit much higher power consumption than the integrated graphics on both platforms. Disabling them when no heavy graphics processing is needed.


Main articles: Nvidia Optimus and AMD Hybrid Graphics

Nvidia Optimus ™

Nvidia Optimus ™ is a computer GPU switching technology created by Nvidia that can dynamically and seamlessly switch between two graphic cards based on running programs.

AMD Enduro ™

AMD Enduro ™ is a collective brand developed by AMD that features many new technologies that can significantly save power. It was previously named as: PowerXpress and Dynamic Switchable Graphics (DSG). This technology implements a sophisticated system for predicting the need for graphics and switching between graphics cards based on predicted need. This technology also introduces a new power control plan that allows the discrete graphics cards to consume no energy when idling. [10]


Integrated graphics

In personal computers, the integrated graphics processors (IGPs) are mainly manufactured by Intel and AMD and are integrated onto their CPUs . They are known to: [11] [12]

  • Intel HD and Iris Graphics – also known as HD series and Iris series
  • AMD Accelerated Processing Unit (APU) – also known as: fusion

Dedicated graphics cards

The most popular dedicated graphics cards are manufactured by AMD and Nvidia . They are known known as:

  • AMD Radeon
  • Nvidia GeForce

Drivers & OS Support

Most common operating systems have built-in support for this feature. However, the users may download the updated drivers from Nvidia or AMD for better experience.

Windows support

Windows 7 has built-in support for this feature. The system automatically switches between GPUs depending on the program that’s running. However, the user can switch the GPUs manually through device manager or power manager. [13]

Linux support

In the Linux systems, has named patch vga_switcheroo[14] has-been added to the Linux kernel since Version 2.6.34 in order to deal with multiple GPUs . Here, the switch requires a restart of the X Window System to be taken into account.

Ubuntu Control Center allows the user to access vga_switcheroofunctionality through a GUI .

Mac OS support

Mac OS has built-in support for this feature since v10.5 Leopard. Since OS X Mountain Lion , Apple has integrated the GPU monitor into the Activity Monitor. [15]

Existing troubles

  • System incompatibility or unstable power supply may cause Blue Screen of Death or other bugs
  • Unable to switch the system
  • Switching may cause unstable voltage which can lead to flashy screen

See also

  • Graphics processing unit (GPU)
  • Nvidia Optimus
  • ATI Hybrid Graphics


  1. Jump up^ “What is the difference between dedicated graphics and shared graphics? – Quora” . . Retrieved 2016-10-24 .
  2. Jump up^ “What is northbridge?” . Retrieved 2016-11-06 .
  3. Jump up^ “What is northbridge?” . Retrieved 2016-11-06 .
  4. Jump up^ “How Motherboards Work” . HowStuffWorks . 2005-07-20 . Retrieved 2016-11-06 .
  5. Jump up^ “What is southbridge?” . Retrieved 2016-11-06 .
  6. Jump up^ “ARK | Your Source for Intel® Product Specifications” . Intel® ARK (Product Specs) . Retrieved 2016-10-24 .
  7. Jump up^ “What’s New | GeForce” . . Retrieved 2016-10-24 .
  8. Jump up^ “Notebook / Laptop Reviews and News” . . Retrieved 2016-10-24 .
  9. Jump up^ “Graphics, Processors and Immersive VR Solutions | AMD” . . Retrieved 2016-10-24 .
  10. Jump up^ “Enduro ™ Power Management Technologies | AMD” . . Retrieved 2016-11-06 .
  11. Jump up^ “The History Of Intel CPUs” . Tom’s Hardware . 2016-06-11 . Retrieved 2016-10-24 .
  12. Jump up^ “The History Of AMD CPUs” . Tom’s Hardware . 2016-04-25 . Retrieved 2016-10-24 .
  13. Jump up^ “Manually activating power management in Windows 7” . . Retrieved 2016-10-24 .
  14. Jump up^ “HybridGraphics – Community Help Wiki” . . Retrieved 2016-10-24 .
  15. Jump up^ “MacBook Pro: How to determine which graphics processor is in use” . Apple Support . Retrieved 2016-10-24 .

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