How to Connect Multiple Video Cards
As video card technology continues to advance, both ATi and nVidia have implemented features into their cards that allow for more than one video card to be installed on a motherboard. In order to use these features properly, you need a certain type of motherboard as well as at least two video cards. Once you obtain the hardware, the process of connecting them is very simple.
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Things You'll Need
- Motherboard with SLI or Crossfire support
- 2 or more video cards of the same model
- Video card drivers
- Screwdriver
Instructions
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1
Unplug your PC from the power outlet at either the PC end or directly out of the wall.
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2
Open your computer tower to give you access to your motherboard. Depending on the design of your tower, this will be as easy as sliding the side panel off or opening a door. However, some towers may require you to use a screwdriver to undo screws (located at the corners).
Take a moment to locate all PCI-Express slots (see Resources below). If you have a motherboard that supports either SLI or Crossfire technology, you will have at least two.
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3
Install your video cards by sliding them into the SLI slots. They will lock into place once they are installed. If you have more than two SLI slots, install a card in the highest slot and work your way down.
Remember that in order for SLI or Crossfire to work, all video cards you install have to be the same model. So if you are installing a GeForce 8800 GT, for example, the other card must be a GeForce 8800 GT. It does not matter of the cards come from different manufacturers so long as the chipset is the same.
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Connect the SLI/Crossfire bridge by sliding the bridge down on the SLI/Crossfire slots located on the edge of the card that is facing you. Motherboards that support Crossfire/SLI will come with a small device called a "bridge." This bridge allows the two cards to run as a single card, essentially doubling the GPU's (Graphics Processing Unit) processing power.
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Close the PC tower and turn the computer on.
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Install the appropriate drivers. These drivers can be found through the websites of the video card manufacturers (see Resources below) or on the CD that comes packaged with each card. Once the drivers are installed, the SLI bridge will be detected automatically.
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Tips & Warnings
Do not attempt to install multiple video cards if you have a power supply unit that generates under 500W. Doing so will lead to your PC shutting down and acting improperly due to a lack of power to certain components.
