Wednesday, March 31, 2004
PCI Express Explained
Posted by Suhit Gupta in "ARTICLE" @ 06:14 PM
"For those who haven't heard of it, the short explanation of PCI Express is that it's a new interface that can go far beyond the speed of current AGP and PCI buses. This new interface was designed to accommodate the ever-increasing speeds of PC input/output devices. Faster products and technologies on the horizon will enable advances like 10-GHz and faster CPU speeds, faster memory, speedier graphics cards, quicker storage, and other high-speed devices, plus networking beyond gigabit speeds. But current systems built with the aging PCI interface don't provide the higher bandwidth you'll need to run these faster products."
Enter PCI Express. A new, faster slot that allows most current OS's to boot up without any changes. Performance scalability is achieved through increasing frequency and adding "lanes" to the bus. It is designed for high bandwidth per pin with low overheads and low latency. Multiple virtual channels per physical link are supported. Other features include the ability to comprehend different data structures, low power consumption and power management features, hot swappability and hot pluggability for devices (which is definitely my favorite :)) and packetized and layered protocol architecture. What does this mean for the common user just looking for a speed boost - "Today's typical PCI bus accepts devices like network cards and sound cards and runs at 133MB per second in one direction. PCI-E can send and receive data at the same time; and it decreases the number of wires used to connect each card. PCI-E ... would allow up to 250MB per second of sustained throughput, yielding up to 4GB per second for each direction with an x16 PCI-E card 8). AnandTech wrote a good article on PCI Express last year and is also worth a read. :)
Enter PCI Express. A new, faster slot that allows most current OS's to boot up without any changes. Performance scalability is achieved through increasing frequency and adding "lanes" to the bus. It is designed for high bandwidth per pin with low overheads and low latency. Multiple virtual channels per physical link are supported. Other features include the ability to comprehend different data structures, low power consumption and power management features, hot swappability and hot pluggability for devices (which is definitely my favorite :)) and packetized and layered protocol architecture. What does this mean for the common user just looking for a speed boost - "Today's typical PCI bus accepts devices like network cards and sound cards and runs at 133MB per second in one direction. PCI-E can send and receive data at the same time; and it decreases the number of wires used to connect each card. PCI-E ... would allow up to 250MB per second of sustained throughput, yielding up to 4GB per second for each direction with an x16 PCI-E card 8). AnandTech wrote a good article on PCI Express last year and is also worth a read. :)
