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PCIe Gen 3 Vs. PCIe Gen 2: What is the difference? Specifications

PCIe Gen 3 Vs. PCIe Gen 2

PCI-Express stands for “Peripheral Component Interconnect Express.” It is referred in an abbreviated form as PCIe or PCI-e. This is the technology that is used for interconnecting system peripherals inside your computer. It is a high standard serial bus standard and is designed to replace the older versions like PC, PCI-X, and AGP. Your PC may come with several connection standards, but PCIe has always been considered to be the best and most advanced option. The two latest versions of PCIe are version 2 and 3 – referred to as PCIe Gen 2 and PCIe Gen 3. How do they compare with each other? Let us find out in the following paragraphs.

A Little About the PCIe Standard

Well, we have explained already that PCIe is a standard for the PC Connectivity. Under the general terms, PCI Express is used for the representation of the expansion slots on the motherboard of your computing device – whether PC or Laptop.

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The PCIe slot will accept PCIe based expansion cards and similar other types of expansion cards in themselves. There have been separate formats of PCIe, and a few of them are named as PCI Express x1, PCI Express 3, and PCI Express 2. Now that PCIe version has almost gone obsolete, we will concentrate on PCI Express 2 and PCI Express 3.

PCIe Gen 3 Vs. PCIe Gen 2 – The Difference

PCIe Gen 3 Vs. PCIe Gen 2

PCI-SIG developed PCI Express 2 or PCIe 2 in 2007. It offers you two times the transfer rate provided by the PCIe version 1. The PCIe 3 was launched later on in the same year in 2007. It gives you a higher bit rate at 8 Giga transfer per second.

That would be the minor difference between the two variants of the peripheral connectivity standards. Given the fact that the standards were released the same year, there are not many paramount differences.

How would you differentiate both these Connection Standards?

The PCI Express would be specified using the number on any of the systems that you would encounter. The version is indicated by a specific number along with the standard supported by the system.

The PCI-Express 2 standard supports 4 Gbits per lane, while PCI express version 3 will support 8 Gbits per lane. It also comes with a few additional specifications and functional performance. In fact, the PCI Express 2 version offers you double transfer rate than that provided by the PCI Express version 1. The per lane throughput has also been enhanced from 250 Mbps to 500 Mbps.

Similarly, PCI Express 3 offers you enhance encoding. This is reinforced by 8b/10b encoding to the 128b/130b encoding scheme. This turns helpful in reducing the bandwidth overhead from 20 percent to 1.38 percent in PCI Express 3.0.

Further Comparison Between PCIe 2 and PCIe 3

Well, the PCI Express 2 and PCI Express 3 differ in a few aspects. However, they do share a few features between them.

Both PCIe 2 and PCIe 3 will be both forward and backward compatible. However, you should understand that the compatibility would be working just for a minimum level. In any case, no matter what version your computer is capable of supporting, we would expect them to work together.

With no need to explain it further, you should understand that each updated version will bring along with it bug fixes, extra features and improvements to power management.

The Concise Information About PCIe 2 and PCIe 3

Well, let us compile the essential features and functionalities of both PCI Express 2 and PCI Express 3 separately so that the comparison would be more straightforward.

PCI Express 2 –

  • The PCI Express 2.0 was launched in 2007.
  • Transfer rate offered by PCIe 2.0 is double than in the PCIe version 1. In fact, PCIe almost doubles it.
  • The higher rate of Throughput. Throughput per lane reads 500 MB per sec.

PCI Express 3 –

  • The PCI Express 3.0 standard was launched in 2010.
  • The transfer speed is equivalent to PCI Express 2.0. But, the speeds in communication rate much higher.
  • It can come with a vast number of protocol management improvements.
  • The Transfer rate per lane reads a maximum of up to 1 Gpbs.
  • The CPU supports the PCIe 3.0 standards. This is in sharp contrast to PCI Express 2.0
  • The protocol is mostly observed in x86 based Intel & AMD chipsets.

This should give you enough information on the fundamental differences between the PCIe 2 and PCIe 3. However, if we go more deeply into these concepts can, in fact, can help you gather more information – but that would be something beyond the purpose and scope of this post.

The Application Areas (PCIe Gen 3 Vs. PCIe Gen 2)

Where would you find these PCI Express communication being used? Though not in direct relation to the purpose of this article, the information can be quite handy. Here are a few areas that the standard has been in use

Please note that this is just a representative list and not an exhaustive one at that. There are many more areas that make use of the standards.

A Tabulated Differentiation For Clear Understanding (PCIe Gen 3 Vs. PCIe Gen 2)

A tabular form of comparison between the two standards of communication can be the best option if you want to go into a better differentiation. Here is an attempt at making a side by side comparison between the two competing communication standards.

Features /ParticularsPCI Express Gen 2PCI Express Gen 3
Raw Bit Rate5 Gigabits per sec8 Gigabits per sec
Link Bandwidth4 GB per sec8 GB per sec
Bandwidth per Lane500 MB per sec1 GB per sec
Total Bandwidth for 16 Port16 GB per sec32 GB per sec
Backward CompatibilityYesYes
Forward CompatibilityYes, but limitedYes

In Conclusion

That should conclude our discussion on the difference between the PCIe Gen 3 Vs. PCIe Gen 2. We assume that we have been able to let you understand the basic concepts involved in both the standards. It should be noted that both PCIe 2 and PCIe 3 come with the same architecture, but are only upgraded to meet the demands of growing performance demands.

Also to be noted is the fact that higher bandwidth may not necessarily provide you better performance. It should be dependent on the limitation and the other issues concerning the software layer.

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