Before you buy a new Graphic Card, make sure that your Motherboard support PCI Express(PCe) or AGP ?
If your motherboard support PCe then buy one, don't buy AGP.
If your motherboard support AGP then buy one, don't buy PCe.
If you plan to buy a new PC, then buy PCe, don't buy AGP. why ? because AGP's about to vanish / out of date technology.
And beside that, PCe' fully supported by Direct X 9 and AGP not. This will give you a better graphics in gaming/graphical experience.
The best one for now' PCI Express / PCe.
Second one's AGP (about to vanish). third one' PCI (old one).
Here's some explamation for them :
PCI EXPRESS / PCe
is an implementation of the PCI computer bus that uses existing PCI programming concepts, but bases it on a completely different and much faster serial physical-layer communications protocol. PCI Express was formerly known as Arapaho or 3GIO for 3rd Generation I/O. PCIe transfers data at 250 MB/s per lane to a maximum of 32 lanes, a total combined transfer rate of 8 GB/s. It must be noted that PCIe is able to transfer data in both directions at once (full-duplex). This effectively doubles the data transfer rate allowing 500 MB/s per lane giving a total combined transfer rate of 16 GB/s when 32 lanes are employed.
Source :
http://en.wikipedia.org/wiki/PCI_Express
AGP / Accelerated Graphic Port
is a high-speed point-to-point channel for attaching a graphics card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Some motherboards have been built with multiple independent AGP slots. AGP has almost completely been phased out in favor of PCI Express.
Advantages over PCI
As computers became increasingly graphically oriented, successive generations of graphics adapters began to push the limits of the PCI bus, leading to the development of the AGP bus, dedicated to graphics adapters. Most motherboards manufactured since the late 1990s include either an on-board integrated AGP adapter, or a physical AGP slot into which a separate AGP-based graphics card can be inserted.
For the needs of modern graphics adapters, the AGP bus is superior to PCI because it provides a dedicated pathway between the slot and the processor, allowing for faster communication between the two. AGP also uses sideband addressing, meaning that addressing for packets is carried outside of the packet, so the entire packet does not need to be read to get addressing information. In addition, to load a texture, a PCI graphics card must copy it from the system's RAM into the card's framebuffer, whereas an AGP card is capable of reading textures directly from system RAM using the Graphics Address Remapping Table (GART). GART reapportions main memory for texture storage, allowing the graphics card to access them directly.
The two main reasons graphics cards with the PCI interface are produced is that first they can be used in nearly any PC, as very few modern desktop PCs do not have PCI slots — though some motherboards with built-in graphics adapters lack an AGP slot. Second, a user with an appropriate operating system can use several PCI graphics cards (or several PCI graphics cards in combination with one AGP card) simultaneously — to give many different video outputs (for the use of many screens). This cannot be done with AGP 1.0 (early AGP 1x and 2x) and AGP 2.0 (AGP 4x) cards, because they do not support more than one AGP Master (videocard piece) per AGP Target (chipset piece). However, AGP 3.0 (AGP 8x) does support more than one AGP Master per AGP Target; but very few PC (if any) motherboards are equipped with more than one AGP slot, but RISC computers, like HP AlphaServer GS1280 can have up to 16 AGP slots, AlphaServer ES80 up to 4 AGP slots and AlphaServer ES47 up to 2 AGP slots in a single system.
Source :
http://en.wikipedia.org/wiki/Accelerated_Graphics_Port
PCI / Peripheral Component Interconnect
The Peripheral Component Interconnect, or PCI Standard (in practice almost always shortened to PCI) specifies a computer bus for attaching peripheral devices to a computer motherboard. These devices can take any one of the following forms:
* An integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification.
* An expansion card that fits in sockets.
The PCI bus is common in modern PCs, where it has displaced ISA and VESA Local Bus as the standard expansion bus, but it also appears in many other computer types. The bus will eventually be succeeded by PCI Express, which is standard in most new computers, and other technologies.
The PCI specification covers the physical size of the bus (including wire spacing), electrical characteristics, bus timing, and protocols. The specification can be purchased from the PCI Special Interest Group (PCISIG).
Source :
http://en.wikipedia.org/wiki/Peripheral_Component_Interconnect
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