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Understanding PCI Express (PCIe) in a Simple Way!

Whether we talk about the PCI (Parallel Component Interconnect), PATA (Parallel Advanced Technology Attachment), or the AGP (Accelerated Graphics Port), PCIe has dominated all these interfaces in most of the terms.

All technologies used to use parallel transmission which offered a great speed in the old days. But, in today’s modern world, the data transmission technique and hence all these older technologies are not enough to deliver the desired data speeds.

Whenever we try to increase the frequency in the parallel transmission schemes, the chances of data corruption increase. Plus, the latency rates start to touch sky heights. So, these connections can achieve limited read/write speeds. But, PCI Express has somehow tackled this problem and that’s the reason why we can now have massive performances from the devices like RTX 3080 or Intel Optane 905P.

PCIe or PCI Express or Parallel Component Interconnect Express has completely dominated the computer industry. And, we are going to know why it’s so effective and popular.

What basically is PCIe (PCI Express)?

Before discussing the definition, you should know that the PCIe is basically made to replace the old-school PCI bus and the AGP bus as well. It uses serial transmission. So, it is possible to increase the data read/write speeds whether you want to install an expansion card or a graphics card.

PCIe stands for Peripheral Component Interconnect Express. It is basically an expansion bus standard using high-speed serial connections. These days, it is a very common motherboard interface used to connect Graphics Cards, RAID Cards, Wi-Fi Cards, Sound Cards, SSDs, and various other high-speed components.

The biggest advantage we receive with the PCIe motherboards is that we have the ability to connect our high-speed hardware components to the system. However, there are certain confusions with the PCIe itself. I will try to clear them below.

Difference between PCI/AGP and PCIe?

In the earlier times, and in the older motherboards, AGP and PCI interfaces were used. The AGP ports were specifically used to connect graphics cards and the PCI ports for almost everything else.

Now, with PCIe, you can connect almost anything to your board. The main difference between AGP and PCI is that AGP is a port whereas PCI is a bus.

The AGP has a higher transfer rate as compared to the PCI. The PCI bus can have up to 132MB/s transfer speed whereas the AGP normally has around 2,133 MB/s. The AGP has higher speeds but as we discussed earlier, it is limited only to graphic cards.

The PCIe not only has speed advantages but also works as a universal slot. We can say that in the current scenario, PCIe is helping us get a lot of advantages over AGP, PCI, and numerous other interfaces.

The PCIe devices can use less or more bandwidth according to the physical lanes dedicated to them. In simple words, 16x PCIe 3.0 devices connected to a 16x slot will have much more bandwidth as compared to the same device connected to PCIe 3.0 8x port. We are going to take about various versions of PCIe and their speeds below.

What are the benefits of PCIe?

The biggest advantage of PCIe is that it has a large bandwidth. It can work with 16 lanes for the data transfer process. The most popular PCIe version i.e. PCIe 3.0 can offer you a transfer speed of up to 16 GB/s on the 16x slot. Along with that, PCIe has a lesser latency which makes it best for all high-speed devices.

As the generations of PCIe are moving forward, the transfer rates we are getting with each slot is increasing. It means that the speed of PCIe can be increased as it’s not limited just like PCI, AGP, SATA, and PATA, etc.

The PCIe 5.0 motherboards can offer you speed up to 63 MB/s with its x16 port.

The PCIe 6.0 has also been planned to be launched in 2021 whose read/write speeds are going to be exceptional. In simple words, the PCIe 6.0 x16 will be able to offer a massive 126 GB/s read/write speed.

The next big advantage in my point of view is the M.2 PCIe NVMe. These dedicated NVMe slots are great to decrease the complexity of a motherboard. These ports are mostly powered by PCIe x4 lanes and use the NVMe protocol for data transfer. On SSD Sphere, we keep discussing various things about the SSDs. So, you can read some articles there for sure.

PCIe All Versions Speed

Versionx1 Bandwidthx2 Bandwidthx4 Bandwidthx8 Bandwidthx16 Bandwidth
1.0 250 MB/s500 MB/s1 GB/s2 GB/s4 GB/s
2.0 500 MB/s1 GB/s2 GB/s4 GB/s8 GB/s
3.0985 MB/s1.969 GB/s3.938 GB/s7.877 GB/s15.754 GB/s
4.0 1.969 GB/s3.938 GB/s7.877 GB/s15.754 GB/s31.508 GB/s
5.0 3.938 GB/s7.877 GB/s15.754 GB/s31.508 GB/s63.015 GB/s
6.0 (Soon)7.877 GB/s15.754 GB/s31.508 GB/s63.015 GB/s126 GB/s
Source: Wikipedia

With the PCIe versions increasing to the next level, lesser lanes are becoming capable of transferring huge data sets. With this sort of scalability, we can say that the upcoming days are going to be much more amazing in the computer industry.

Understanding PCIe Form Factor

Note: The traditional PCIe can always be seen on desktop motherboards and never inside laptops. The laptops however come with the M.2 PCIe NVMe ports supporting only the M.2 devices.

You can see five different types of standard PCIe ports on a motherboard. x1, x2, x4, x8, and x16. Although x2 and x4 ports are rare. x on your port indicates how many physical lanes are allocated to that port. However, there are two other main types of PCIe form factors i.e. U.2 and M.2.

PCIe ports will look like this.

The M.2 PCIe NVMe port will look like this. Know more about the M.2 Form Factor here.

There is another form factor of PCIe known as U.2.

How PCIe is dominating the computers market?

It is happening probably because there is no other faster data transfer protocol available these days. PCIe is completely dominating the older storage technologies like SATA. Also, in order to get the most out of our powerful graphics cards and RAID cards, it is important to have a faster port like PCIe.

Also, with the arrival of PCIe, the data Read/Write limits have reached sky heights. Now, we can achieve up to 32GB/s read/write speed if we connect any capable hardware on PCIe 4.0’s x16 port. That speed has almost reached the corporate PC levels and this is the main factor improving the computer industry.

What are the PCIe versions and their importance?

The PCIe 1.0 was launched in 2003 and it was like a revolution at that time. People were amazed by seeing its huge data transfer speed. PCIe kept improving with its 2.0 version launched in 2007 and 3.0 in 2010. The PCIe 3.0 kept the latest in the market for around seven years when the PCIe 4.0 launched in 4.0.

With the PCIe 5.0, things start to become much more capable and now when PCIe 6.0 is going to be launched in 2021, we are going to see much more improvement. So, you can see that with the increasing number of PCIe versions, the speed is increasing exponentially and that is what we want to get from technology.

How does PCIe benefits the storage technology?

SSD Sphere is focused mainly on storage technology and specifically on SSDs. And, I would admit that the PCIe has totally changed the way how data is read and written on/from the storage devices.

In the earlier times, when hard disks were using the SATA and PATA protocols, the data reading and writing speeds were very low. But, with the help of PCIe Add-in Cards and mainly M.2 PCIe NVMe SSDs, we can easily reach up to several GB/s data read/write speeds.

The M.2 NVMe SSDs are dominating the computer storage market and PCIe is the main reason behind it. I would like to see some more growth in this technology in the upcoming days.

Thanks for reading!!!

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