PCI Express, often referred to as PCI-E or PCIe, is a computer bus technology that allows expansion cards to communicate with the computer's processor. PCI-E slots started appearing on computer motherboards in 2004 and have since gained popularity over older and slower PCI and AGP slots. Installing a PCI-E card is much like installing other cards, but it has its own slot and often requires an additional power connection.
Turn off the computer and unplug all the cables from the back of it. Make sure that you record on the paper which plugs the cables go into, since you will have to put them back shortly.
Remove the computer case. Some cases require removal of some screws on the back of the computer before sliding the case off, and others may have a latch that must be pulled to release the case. The exact process will be different for every model of computer, so consult the user's manual or the manufacturer's website for specific directions.
Locate an open PCI-E slot. The PCI-E slots typically are black, although they can be any colour. The slot will have one small section about half an inch long, followed by a much longer section. The PCI-E slot also will often have a latch on it, which secures the card once it is in place. The PCI-E slot will be located with the rest of the slots, near the back of the computer.
Remove the metal cover from the opening in the back of the computer where the card will go. There will be a screw holding the cover to the back of the computer. Keep the screw, as you will need it to secure the PCI Express card to the back of the computer. If you are replacing another card, you will not need to do this, as the opening was already there.
Insert the PCI-E card into the slot. Orient the card so the connectors on the backing plate are pointing through the opening you just created in the back of the computer. Press down on the centre of the card until it slides into place.
Place a screw in the small cutout on the metal backing plate. Screw the backing plate into the back of the computer.
Attach a power cable to the PCI-E card, if necessary. Some cards, especially high-end graphics cards, require more power than they can get through the PCI-E slot. In this case, plug one of the 4-pin cables coming from the power supply into a receptor on the card.
Close the computer case and reattach all the cables. Turn on the computer and place the installation disc that came with the PCI Express card in the CD-ROM drive. The installation software should run automatically, so just follow the prompts to install the card software.
Discharge yourself by touching something metal before you touch any computer component.