What is the difference between PCI, PCI Express and PC?
The terms “PCI”, “PCI-X” , “PCI-Express” (or PCIe) are often used interchangeably, but do mean different standards. Since each of these terms has been used to describe several generations of expansion buses, it’s easy to get confused. For example, some people say that they have 32-bit PCI cards in their 64-bit machines or that they want a motherboard with at least one 686 bus (686 is an obsolete term for AGP). But hopefully this list can clear up what each of these specifications entails:
A standard originally developed by Intel in 1992 for attaching peripheral devices to a computer bus. It was known as the “Accelerated Graphics Port” and allowed for very high speed communication between a video card and a computer, making it an ideal choice for things like 3D gaming. All Intel and VIA chipsets since then have been PCI compatible.
A later version of PCI developed by Intel in 1998 that increased the maximum bandwidth from 132 MB/s to over 1 GB/s (and even up to 4 GB/s with 64-bit PCI-X). The new bus type used smaller packets, which reduced electrical loads and thus improved CPU efficiency through lower latency for data passing through the CPU’s memory controller hub .
The PCI Express specification is also a derivation of the PCI bus definition. It is different in that it uses a packet-based link protocol with multiplexed communications, rather than the original shared-bus mechanism of PCI .
What was AGP?
AGP stands for Accelerated Graphics Port and was an Intel-specific interconnect used to send video data from the CPU/northbridge (where the CPU’s memory controller hub lives) to the northbridge’s companion graphics chip (the northbridge includes integrated display hardware). The early AGP specification allowed for up to 2 GB/s of bandwidth assuming 32 bits wide, though later revisions increased this to 4 GB/s with 64 bits wide (though even using 128-bit transfers it would still be limited by the PCI-X specification of 133 MB/s). Both AGPx8 and AGPx16 were eventually obsoleted by the PCI-Express 2.0 specification.
What is PCI-X?
PCI eXtended (or just PC iX) was an older term for PCI Express, especially when talking about older 32-bit versions of the standard. Never mind that even though “PCI Express” is now considered standard, previous generations are still often referred to as “PCI-X”. It’s good to be aware that even though everything has moved on to PCIe, some people might still refer to it as PCI-X or maybe even PCI -E.0 or 1.1, etc.
What is the difference between PCI-E 2.0 and 3.0?
The second generation of PCI Express (commonly called PCIe 2. x ) has a raw speed limit of 500 MB/s per lane, which can be combined to make higher speeds like 10 GB/s (10,000 MB/s) over a 16-lane slot (x16). The third generation doubles this to 1 GB/s per lane for an aggregated bandwidth of 32 GB/s over a sixteen-lane slot (x16), making it faster than most current PCI-E slots allow for.
What are the types of PCIe connectors?
There are many different types of PCIe connectors, but they’re pretty easy to identify once you know what a full-size and short PCI-e card looks like. The standard full-length PCIe cards are 16cm long, but the connector itself is about 1cm longer, making them 17cm from tip to toe. A full-sized PCIe card has a gap of 2mm between it and the slot it’s plugged into. In contrast, a shorter PCIe card (also known as a “half-height” or “low profile” type) is only 10cm from tip to toe . The gap for these smaller cards is 3mm, allowing for slightly thicker heatsinks on the card itself.
What Type should I use?
PCI Express x1 is best for devices that don’t require much bandwidth. The x1 lanes operate at 2.5gb/s and can be combined to yield a 5gb/s link speed, making it suitable for things like USB 3.0 adapters or other simple add-ons that require low power and little data throughput. You’d only want to use x2, x4, x8, and x16 if you had a device with a higher requirement for bandwidth and also required significant amounts of electrical power (x1 cards will only accept up to 25 watts).