Why Are the Pci Express Ports on My Motherboard Different Sizes?

PCI Express slots are rectangular and protrude from the Motherboard , with several terminals on either side. PCI Express slots come in various shapes and sizes, including x1, x4, x8, and x16. The slot is divided into two parts; the first is consistent across all slots and serves as the KEY, while the second component varies according to the number of PCIe lanes. These slots are frequently located near the computer's casing IO shield on the Motherboard series. Many expansion cards installed in PCIe slots expose some ports to the outside world.

This finest lga 1150 motherboard features two PCI Express x16 slots, two PCI Express x1 slots, and two PCI slots for adding additional components such as graphics cards, audio cards, and more.

In the recent decade, almost every desktop computer has included PCI Express. Yet, the connectivity is somewhat vague: on a new PC, you may discover a half-dozen ports of varied sizes, all marked "PCIE" or "PCI-E." Thus, why the dismay, and which ones are genuinely usable?

PCI Express Bus

PCI Express was created in the early 2000s to replace the old PCI system. Notably, it employed a point-to-point accessing bus instead of a serial bus. This allowed each PCI port and its attached cards to operate at full speed without clogging the bus with several cards or expansions. The entire computer can quickly access components and accessories when each expansion card or accessory has its dedicated data channel.

PCI Express Lanes

Since its debut, PCI-E has undergone numerous upgrades; today, most new motherboards utilize version 3, with speedier version 4 becoming more prevalent. However, all revisions use the same physical connectors in four major sizes: x1, x4, x8, and x16 (x32 ports exist, but they are exceedingly uncommon and not typically found on consumer devices.)

Multiple data pins can be connected to the motherboard simultaneously because of the different physical sizes of the ports; the more connections on the card and port there are, the higher the port size. These connections are informally referred to as "lanes," Each PCI-E lane consists of two signaling pairs, one for transmitting data and one for receiving data. PCI-E upgrades allow for varying speeds in each channel. However, data transfer between a PCI-E peripheral and the remainder of the computer system is faster when a PCI-E port has more lanes.

Which Port Connects Which Peripherals?

The highest per-lane data throughput for PCI Express revision 3.0 is eight Giga transfers, a word that refers to "all data and electronic overhead at once." In practice, PCI-E revision three speeds are slightly less than one gigabit per second per lane.

Thus, a device with a PCI-E x1 port such as a Wi-Fi antenna or a low-power sound card can send data to the rest of the computer at roughly 1GBps. A device that fills the physically bigger x4 or x8 slot, as in a USB 3.0 expansion card, can transmit data 4 or 8 times faster—and it'd have to if more than 2 USB ports were functioning at maximum speed. PCI-E x16 connections, which have a theoretical maximum bandwidth of around 15GBps in the 3.0 revision, are used by practically all recent graphics cards built by NVIDIA and AMD.

There are no predefined rules about which expansion cards will utilize which amount of lanes. Though graphics cards commonly use x16 for maximum data transmission, if your network card's Ethernet port can only carry data at one gb/s, you don't need an x16 port and sixteen complete lanes. Although a few PCI-E-mounted solid-state drives necessitate an x4 connection, they seem to have been soon displaced by the modern M.2 standard, which also supports the PCI-E bus. High-end network cards and enthusiasts' gear (adapters and RAID controllers) utilize both the x4 and x8 formats interchangeably.

Bear in Mind: The PCI-E Port size and the Lanes Count May Not Be Identical.

A port may have the physical dimensions of an x16 card yet only have enough data lanes for a significantly slower card, such as x4. While PCI-E can theoretically support an infinite number of individual connections, the chipset's lane throughput is still restricted. Cheaper motherboards with less expensive chipsets may only support a single x8 slot, even if the slot physically supports an x16 card. Meanwhile, "gamer" motherboards will feature up to four full-size and x16-lane PCI-E slots to ensure optimum GPU compatibility.

This can create complications. Assuming your motherboard contains two x16-sized slots, yet one only has x4 lanes, putting your new graphics card in the wrong one can impair productivity by up to 75%. Of fact, that is a theoretical outcome; the architecture of motherboards precludes such a severe drop. A genuine card must be placed into the proper slot.

Fortunately, the lane capacity of each PCI slot is typically specified in the computer or motherboard manual, along with an image indicating which slot has which capacity.

Moreover, the initial pin configuration of the electrical contacts allows shorter cards to physically fit into longer ones. Although the card is physically a little flimsy, it is more than suitable when slotted into the expansion slots of a PC chassis. Naturally, A card cannot be installed if its contacts exceed the slot's physical dimensions.

Therefore, while purchasing expansion or upgrade cards for PCI Express slots, keep in mind both the available ports' physical size and lane rating.