PCIe is a high-speed standard that allows you to add extra functionalities to your motherboard with the help of expansion cards.
These cards get attached to PCIe slots found on the motherboard and thus add functionality such as Video Graphic Processing, network capability or storage expansion.
These devices need to communicate and share data with the CPU to carry out their tasks.
To facilitate this connection, we have PCIe lanes. These lanes serve as the information highway through which bits of data are transferred from the PCIe device to the CPU for processing. In the following text, we read more about what are PCIe lanes.
What Are PCIe Lanes?
A PCIe express lane is basically a pipeline for sending data back and forth between the PCIe device and the CPU.
Every new generation of PCIe increases the per-lane speed to double. For example, PCIe V3.0 is twice as fast as PCIe V2.0.
Similarly, a processor with a faster clock speed cycle would move the data across the lanes faster.
X1 is the smallest connection as it donates a single lane. This connection is suitable for devices that require very little data transfer like sound cards.
The more lanes a slot has, the higher is it speed multiplies. So if x1 slot has a single lane with 1.0 GB/s transfer speed, the x4 slot with 4 lanes will have 4.0 GB/s transfer speed.
You Don’t Have Unlimited Lanes
There is a finite number of PCIe lanes every computer has. The number depends upon the CPU and the motherboard chipset.
CPU Lanes
Typical Intel processors give you about 16 lanes of dedicated PCIe lanes for their 10th gen processors.
A typical processor has enough PCIe lanes for a single X16 Graphics Card working at full X16 mode or two Graphics Cards working at X8 / X8 mode.
The workstation-grade processor gives more than 16-24 PCIe lanes.
An Intel X Series processor above, for instance, offers 44 PCIe lanes.
Motherboard Chipset Lanes
You also get some PCIe lanes from the motherboard chipset. This depends upon the chipset of the motherboard.
PCIe Configuration
PCIe slot configuration is offered in X1, X4, X8, and X16 bandwidth sizes. The number after the X prefix denoted the number of lanes available to the slot.
X1 PCIe Slot
This configuration has just one lane. This means that only one path for the data bits to be transmitted to and from the CPU. This is like a single-lane road.
With each generation, the lane-speed of a PCIe interface is usually the same and so to get faster data transfers, we need to increase the number of lanes.
PCIe X4 Slot
This one has four lanes, so quadruple the number of lanes compared to the X1 slot. Since the data rate would be the same per lane, you would, in effect, have 4 bits of data getting transferred to and from the devices in every cycle. This means more bandwidth and hence more data transfer. But it doesn’t stop there.
PCIe X8 Slot
This slot has twice the number of lanes that the X4 slot has. This means that you get four more lanes through which data can be transferred with every clock cycle.
This, of course, has additional bandwidth and is, therefore, better than the X4 slot under applications that can make use of all the available lanes.
This brings us to the largest widely available largest configuration.
PCIe X16 Slot
With this configuration, you get 16 data lanes that can be used to transmit 16 bits of data with each cycle.
This results in faster transfers as a result of the larger bandwidths and is ideal for bandwidth-intensive devices like graphics card.
Conclusion
Here we basically looked at What are PCIe lanes from a consumer perspective. Knowing what a PCIe lane is and how it defines your PC builds is crucial for any enthusiast.
In technical terms, PCIe lanes are vital for communication between a computer’s CPU and the peripheral devices attached to the motherboard.
The important thing to note about the lanes is that the more lanes on a slot, the more bandwidth you can have if you connect a suitable device to the slot.
Another important thing to note is that different devices require a different number of lanes. Powerful devices like graphics cards require a very fast transfer speed and thus require larger 16-lane PCIe slots. Networks cards, on the other hand, can be fitted on a single-lane slot.
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