How to Identify Motherboard Video Card Slots

Written by: Bill Fulks • Edited by: M.S. Smith
Published May 23, 2010 • Related Guides: ASUS

Video cards are not one size fits all, so you need to know what your motherboard supports before you buy one.

What Kind of Video Card Should I Buy?

Motherboard video card slots come in three main different types: PCI, AGP, and PCI Express. The connectors are physically different for each card type, and they are not interchangeable. Furthermore, there are different submodels beneath these three main types. When looking to buy a new video card or updating the one you already have for your computer, you need to be very careful what you buy or else it may not work. In this article, we'll look at the different motherboard video card slots and how to identify them so you get the right video card for your computer.

PCI Motherboard Video Card Slots

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PCI slots are the oldest type motherboard connectors are are used for video cards as well as other card-based upgrades like sound cards, modems, and much more. When it comes to video cards, PCI types are the oldest and slowest in terms of speed, so they aren't that well suited to modern gaming unless you have no other option.

In the image to the right, you will see four PCI slots as they appear on a motherboard. They are most often going to be white in color, and have a small divider about once inch in from one side. PCI video cards will have a notch at the bottom to fit into this divider so that you can't accidentally put the card in backwards. The easiest way to pick out the PCI slots is that your computer will most likely have more of them than any other, and they are typically placed right next to each other.

AGP Motherboard Video Card Slots

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AGP video card slots are pretty much outdated, though still better than PCI for speed. These cards use multipliers going up to 8X in order to enhance performance, but that depends on the type of motherboard you have and whether or not it is supported. AGP comes in three versions - 1.0, 2.0, and 3.0. Watch out buying a used AGP video card that may be 1.0, as it is much preferred to have 2.0 or 3.0. If AGP is your only choice, there are still some good AGP cards available.

Most AGP slots will be in a color that is different from the other slots. In the photo to the right, you will see that the AGP slot is colored brown, as is typical of most motherboards. AGP slots also have a tab at one end that is used to hold the card in place. Some AGP slots will have a divider in them, and this indicates the voltage (1.5V or 3.3V) for the slot, which in turn can determine what kind of video card you should buy. In the included photo here, this motherboard uses the universal AGP slot design that has no dividers.

PCI Express Motherboard Video Card Slots

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The most modern form of video card uses the PCI Express, or PCIE, motherboard video card slot. Personally, I wish they had been named something else because novice computer users tend to confuse PCI Express card types with regular PCI, and they are both completely different and not swappable.

In the image to the right, you will see an ASUS brand motherboard that has both PCI Express x1 and PCI Express x16 slots. The smallest white connector in the lower left side is the PCI Express x1 slot, which is still used for some early model video cards and peripherals, but not all that common today. The two blue slots are both PCI Express x16, which is the most modern form factor. This particular motherboard is configured so that you could connect two video cards together for even more power. The other two white connectors are regular PCI slots, which you can see are slightly smaller than the blue PCI Express x16 slots.