What is and what is the PCI Express port for?

What is the PCI Express port and what is it for

PCI Espress has become the expansion slot standard for connecting various devices to computers. We explain the importance of this interface, and what are its main uses.

What is PCI Express and what features does it have

PCI Express , abbreviated as PCI-E or PCIe , is an evolution of the classic PCI interface that greatly improves its usability and performance. Since its arrival on the market in 2004, it has not stopped evolving to improve its performance more and more.

PCI Express is a data bus that works in parallel and connects directly to the processor of a computer or to the chipset and from there to the processor. The PCI Express interface is divided into channels through which the data circulates , and there may be versions of 1, 2, 4, 8, 12, 16 and 32 lanes.

pci express slots

Different types of PCI Express slots on a motherboard

The most widely used version today is PCI Expres 3.0, which is capable of offering 1 GB / s for each lane , so that a 16-lane bus will offer a whopping 16 GB / s. PCI Express 4.0 is the new version, which doubles the speed of version 3.0, but there are hardly any devices on the market that can take advantage of it.

The following table summarizes the speeds of the most commonly used PCI Express interfaces.

PCI Express 1.0 x1250
PCI Express 1.0 x41,000
PCI Express 1.0 x82,000
PCI Express 1.0 x164,000
PCI Express 2.0 x1500
PCI Express 2.0 x42,000
PCI Express 2.0 x84,000
PCI Express 2.0 x168,000
PCI Express 3.0 x11,000
PCI Express 3.0 x44,000
PCI Express 3.0 x88,000
PCI Express 3.0 x1616,000
PCI Express 4.0 x12,000
PCI Express 4.0 x48,000
PCI Express 4.0 x816,000
PCI Express 4.0 x1632,000

What is the PCI Express interface for

PCI Express is a bus that is used to connect a multitude of devices to the motherboard of a computer. This interface is gradually replacing other types of connection such as SATA, as it offers much superior technical characteristics.

Connect graphics cards

The main use of the PCI Express port is to connect graphics cards to the motherboard. Graphics cards require high bandwidth to work, so a 16-lane PCI Express interface is perfect for these devices. In the past, graphics cards were connected by AGP, but it has been many years since this port has been used anymore.

pci express graphics card

PCI Express also allows the use of several graphics cards on the same PC, it is what is known as Nvidia SLI and AMD CrossFireX configurations, although this is less popular every day due to the many inconveniences it entails compared to using a single more powerful card.

High-speed NVMe-based SSDs

The most advanced SSD storage units also make use of the PCI Express interface , which allows data transfer speeds to be achieved much higher than traditional SATA ports. While a SATA 3 port is capped at 600MB / s, an SSD with a 4-lane PCI Express 3.0 bus can go as high as 3,200MB / s, and PCI Express 4.0 SSDs are expected to hit nearly 8,000. MB / s.

ssd pci express

Expansion cards

In laptops, the PCI Express interface is also used to connect a small card that adds WiFi and Bluetoth connectivity to these computers, something essential today. The use of the PCI Express interface does not end there, as it can also be used for many other devices such as sound cards, capture cards, network cards, cards with additional USB ports and many other devices.

Computer clusters

In the professional sector, the use of the PCI Express interface allows several computers to be connected together using HyperTransport technology . This makes it easy to scale power and performance.

These are the main uses of the PCI Express port.