1. Originally introduced as PCMCIA Card, the PC Card standard as well as its successors like CardBus were defined and developed by the Personal Computer Memory Card International Association (PCMCIA). It was originally designed as a standard for memory-expansion cards for computer storage.
2. Short for Personal Computer Memory Card InternationalAssociation, and pronounced as separate letters, PCMCIA is an organization consisting of some 500 companies that has developed a standard for small, credit card-sized devices, calledPC Cards. Originally designed for adding memory to portable computers, the PCMCIA standard has been expanded several times and is now suitable for many types of devices. There are in fact three types of PCMCIA cards. All three have the same rectangular size (85.6 by 54 millimeters), but different widths

   
   

   Type I cards can be up to 3.3 mm thick, and are used primarily for adding additional ROM or RAM to a computer.

   • Type II cards can be up to 5.5 mm thick. These cards are often used for modem and fax modem cards.

   Type III cards can be up to 10.5 mm thick, which is sufficiently large for portable disk drives.

   A Type I slot can hold one Type I card

   • A Type II slot can hold one Type II card or one Type I card

   A Type III slot can hold one Type III card or any combination of two Type I or II cards.

   
   

   As with the cards, PCMCIA slots also come in three sizes:

   In general, you can exchange PC Cards on the fly, without rebooting your computer. For example, you can slip in a fax modem card when you want to send a faxand then, when you're done, replace the fax modem card with a memory card.

AGP

Short for Accelerated Graphics Port, AGP is an advanced port designed for Video cards and 3D accelerators. Designed by Intel and introduced in August of 1997, AGP introduces a dedicated point-to-point channel that allows the graphics controller direct access the system memory. Below is an illustration of what the AGP slot may look like on your motherboard.

The AGP channel is 32-bits wide and runs at 66 MHz. This translates into a total bandwidth of 266 MBps, which is much greater than the PCI bandwidth of up to 133 MBps. AGP also supports two optional faster modes, with throughput of 533 MBps and 1.07 GBps. It also allows 3-D textures to be stored in main memory rather than video memory.

Each computer with AGP support will either have one AGP slot or on-board AGP video. If you needed more than one video card in the computer, you can have one AGP video card and one PCI video card or use a motherboard that supports SLI.

AGP is available in three different versions, the original AGP version mentioned above, AGP 2.0 that was introduced in May of 1998, and AGP 3.0 (AGP 8x) that was introduced in November of 2000. AGP 2.0 added 4x signaling and was capable of operating at 1.5V and AGP 3.0 was capable of double the transfer speeds.

Tip: Not all operating systems support AGP because of limited or no driver support. For example, Windows 95 did not incorporate AGP support. See the Windows versions page for information about Windows versions that support AGP.

Today, AGP is being replaced by PCI Express.

What is AGP Pro?

AGP Pro is an AGP interface extension specification for advanced workstations. This specification delivers additional power to video cards, includes an extended connector, thermal envelope, updated mechanical specifications, I/O bracket, and motherboard layout requirements.

Related pages

• Determining the AGP version.
• Additional information with installing computer hardware.
• Can I add an AGP slot to my computer?
• Video card help and support.
• Computer motherboard help and support.