What is PCI Express - TEQNO Q

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What is PCI Express

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PCI Express
officially abbreviated as PCI-E or PCIe, is a computer expansion card interface format. It was designed to replace PCI, PCI-X and AGP (graphics card interface). PCIe is based around serial links called lanes.

The PCIe 1.1 specification supports x1 (pronounced "by one"), x2, x4, x8, x16, and x32 lanes. In each lane, the most common version PCIe 1.1 carries 250
MB/s in each direction. Every lane of the PCIe is a full duplex link; capable of simultaneous transmit and receive.

The PCIe 1.1 bus runs at 2.5
GHz. An explicit clock is not used; instead the data stream is encoded using the 8b/10b scheme, which ensures that there are sufficient transitions within a single 10 bit character to properly and reliably recover the clock.

The astute reader will notice that there are 4 times more combinations than characters used. Some of these additional characters are discarded due to an insufficient number of edges within the 10 bit packet to extract the
clock.

Others are used to encode error commands. Some may be used to provide "DC balancing" so that the wire doesn't acquire an electrical charge. The remainder are simply not used.
Therefore, each lane transmits 250 MB/s. The most number of lanes supported is x32, so 250MB/s x 32 x 2 (
bi-directionality) is 16GB/s for a theoretical maximum transfer rate.

From Wikipedia

ECS nVidia GeForce 8500GT 256MB DVI/HDTV PCI-Express VGA Card.
* Mfg part number: N8500GT-256DY
* Chipset: GeForce 8500 GT.
* Engine Clock: 500 MHz.
* Video Memory: 256MB DDR2.
* Memory Clock: 860 MHz.
* Memory Interface: 128-bit.
* Bus: PCI-Express x16.
* RAMDAC: 400 MHz.
* Max. Resolution: 2048 x 1536 @ 85Hz.
* Connectors: VGA, DVI, TV-out (HDTV ready).
* Thermal: Fansink.
* Support nVidia SLI Technology.
* Support Microsoft DirectX 10.0, Shader Model 4.0 and OpenGL 2.0.

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