All PCIe Slot Types (Thoroughly Explained)

There is no way to overlook the fact that PCIe slots are very important to any PC. These slots are where we install our GPU and some other supported components, and while modern motherboards have more than one slot, people normally only use one, the one where the GPU is installed.

But what do these PCIe slots mean, in the first place? That is a question that a lot of people ask, and in this post, we are going to make it clear for those who are confused.

If you have ever wondered about the PCIe slot types, this post is for you since we are going to look into everything you need to know.

What Is PCIe or PCI Express?

The first thing that you need to understand is that PCIe or PCI Express stands for Peripheral Component Interconnect Express; while the name itself is a mouthful, it is actually pretty self-explanatory.

PCIe has been around for a long, long time. However, over the time, it has seen generational upgrades and improvements. You use these slots to connect graphic cards, storage devices, network cards, and other devices that share the same interface.

What is a PCI Express slot?

A PCI Express or a PCIe slot is simply a slot that is found on the motherboard, it normally is located on the bottom left side of the motherboard, and you get a number of them on a motherboard; this all depends on the CPU lanes.

These slots can go as high as 16GB/s and even offer a hot swapping feature that lets you unplug an old device and plug in a new one without any issues.

What Are the Different PCI Express Formats?

Considering how PCIe has been around since 2003, we have seen a number of generational upgrades, and with each upgrade, we have only seen better and better performance, as well.

At the time of writing this, there are currently five generations of PCie, with each generation offering double bandwidth than the last, and enabling better performance, especially for storage devices.

PCIe Slot Sizes: x16 vs x8 vs x4 vs x2 vs x1

Similarly, PCIe slots also come in sizes. You start with PCIe x1, then you go to PCIe x4, then you move to PCIe x8, and then the full-sized slot is the PCIe x16.

Now, if you are wondering what the difference is, here is a small bullet list that is going to help you understand.

• ‘PCIe x1’ connections have one data lane
• ‘PCIe x4’ connections have four data lanes
• ‘PCIe x8’ connections have eight data lanes
• ‘PCIe x16’ connections have sixteen data lanes

The more data lanes you have, the more bandwidth you can get between the device that is plugged in and the host.

Almost all the modern graphic cards you see use the x16 slot, with other devices using different slots, as well. It all comes down to how much bandwidth is required, in the first place.

PCIe Slot Versions: 5.0 vs 4.0 vs 3.0 vs 2.0 vs 1.0

Now that you know what each slot is capable of, what about the generations that you are getting? We mentioned earlier that currently, consumers have options of up to PCIe 5.0 generation; however, the 6th generation specifications have been confirmed.

For your convenience, we are sharing a table that shows the generations of each slot, as that will give you a better understanding.

	Bandwidth	Gigatransfer	Frequency
PCIe 1.0	8 GB/s	2.5 GT/s	2.5 GHz
PCIe 2.0	16 GB/s	5 GT/s	5 GHz
PCIe 3.0	32 GB/s	8 GT/s	8 GHz
PCIe 4.0	64 GB/s	16 GT/s	16 GHz
PCIe 5.0	128 GB/s	32 GT/s	32 GHz
PCIe 6.0	256 GB/s	64 GT/s	32 GHz

As far as the PCI 6.0 generation is concerned, the specs, although are confirmed, we haven’t seen devices running on this generation, but that shouldn’t be far as we might get something later this year, and that would make sense.

PCI vs PCIe: Speed

A lot of people often get confused between the PCI and PCIe and the speed they offer. Well, PCI is offered in either 32 or 64-bit, with 133 MB/s and 266 MB/s speeds, respectively.

However, the PCIe speed is a bit more complicated to understand as it Is still developing. Therefore, when you are trying to figure out the speed of the latter, you have to look at the generation, along with the size of the slot, and then you will have a better understanding as to what you are looking at.

So, before you determine, it is always better to compare slot sizes, as that will give you a better understanding.

PCI vs PCIe: Compatibility

In terms of compatibility, the 32-bit PCI interface cannot run 64-bit interfaces, but it does work vice-versa. As for PCIe, considering how it has different lengths, the longer one can support shorter-length PCIe devices but not the other way around.

They are also backward compatible in terms of the version/generation they are on but will run on the max speed of the previous generation.

So, for instance, if you connect your PCIe 3.0 device to a PCIe 2.0 interface, it will operate at the 2.0 speed.

Last but not the least, PCI and PCIe devices are not cross-compatible with each other, and you cannot go ahead and use the devices on different slots.

What Are The Uses of PCIe Slots?

PCIe slots are used for all sorts of purposes. Simply put, you can just go ahead and connect various devices ranging from your usual graphic cards, storage devices, Wi-Fi cards, capture devices, Bluetooth devices, and more.

However, considering how most of the features are now built-in inside the modern motherboards, we normally don’t see a lot of other uses. So, you can just go ahead and connect all the relevant devices whenever you want.

However, be sure that you are connecting the right ones and not getting confused with what needs to be connected and what doesn’t.

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