How to Tell the Difference in AGP and PCI

PCI slots are usually cream color whereas AGP is usually maroon colored.

The PCI (Peripheral Component Interconnect) slot was created in 1990 by Intel as a replacement for the ISA (Industry Standard Architecture) and VESA (VL Local Bus, sometimes called VLB). The system was officially used for the first time in 1994 and as of October, 2010 is still in use in many computers. AGP (Advanced Graphics Port) was also created by Intel in 1997. It was intended to address the problems of bottlenecks in the PCI bus and was designed specifically for graphics cards. The system has several versions, 1x, 2x, 4x and 8x, though the 4x/8x slot is not backward compatible with 1x and 2x AGP since it uses a different level of voltage.

Instructions

1. Look at your motherboard and identify where the expansion slots are. They are long, narrow slots and they will be along one edge of the motherboard. If your motherboard is already installed inside the computer, the slots will be facing the back of the computer.

2. Examine the placement of the slots on your motherboard. The AGP slot will be slightly off center from the PCI slots. There will also likely be more than one PCI slot while there will likely be only one AGP slot.

3. Examine the color of the slots. PCI slots are typically cream color while the AGP slot is typically a darker, maroon color.

Tips & Warnings

• Note that some AGP slots are 1x/2x slots which only support 3.3v AGP cards, some support 1x/2x/4x and can switch between 1.5v and 3.v while others are only capable of supporting 4x/8x AGP. There is no way to tell the difference between them by sight. You will need to consult your motherboard manual to find out what kind of AGP slot you have.

• Note also that as of October, 2010, many computers now use PCIe (PCI Express) cards, which are distinct from both PCI and AGP cards.

• When examining your motherboard to find out what kind of slots you have, be sure to touch the metal part of your computer case before touching the motherboard itself. Failure to do so may cause electric shock to your motherboard, damaging sensitive components.

References

• Hardware Secrets: AGP Bus Tutorial
• PC Tech Guide: AGP
• TopBits: PCI
• Techfest: PCI Local Bus Technical Summary
• Build Your Own Computers: What's the Difference Between AGP, PCI and PCI Express?

Resources

• PC Guide: VESA local bus
• PC Guide: ISA (Industry Standard Architecture
• Directron: What is PCI Express?
• PCI Special Interest Group: PCI-X 2.0 Frequently Asked Questions