A PCIe NVMe SSD is the fastest form of SSD available. To accommodate larger bandwidths, they make use of the high-speed PCIe bus. Most PCIe NVMe SSDs have a 4x PCIe lane connection, however, understanding what a PCIe lane is can be challenging because the literature on the subject is dispersed and difficult to grasp.
The M.2 slot currently uses a maximum of 4 PCIe lanes with current NVMe SSD speeds and the newer PCIe 4.0 version. However, depending on your motherboard setup, the number of PCIe lanes that the M.2 slot utilizes may vary.
How many PCIe Lanes does NVMe use?
M.2 is a high-speed SSD interface that is extensively used today. It has a relatively tiny form factor and is hence regarded as almost necessary for a contemporary configuration. However, unlike previous M.2 SATA SSDs, which use the slower SATA 3 interface, M.2 NVMe SSDs utilize PCIe lanes.
As a result, NVMe SSDs outperform even the fastest Hard Disk Drives and SATA SSDs on the market. The number of PCIe lanes on the M.2 slot, as well as its PCIe version, have a direct influence on its performance. In this article, we will look at how many PCIe lanes each M.2 slot uses, how it is affected by the version and lane count, and best practices for selecting the correct SSDs.
What are PCIe Lanes?
On a motherboard, a PCIe lane is a group of four wires or signal traces. Each lane employs two wires to send data and two wires to receive data, allowing the whole bandwidth to be used in both directions at the same time.
A limited number of PCIe lanes can be supported by each CPU. Consumer-grade Intel CPUs have traditionally supported 16 PCIe lanes, whereas AMD has supported 20. High-end enthusiasts and server CPUs frequently have additional PCIe lanes.
Every day, the demand for a standard for end-to-end communication and efficient flash storage grows. NVMe SSDs link to your device’s PCIe (Peripheral Component Interconnect Express) interface, providing significantly higher speeds than SATA SSDs. But what exactly is PCIe, and how does it affect data read/write speeds?
This post will teach you about PCIe 4.0 NVMEs and why they are a better choice than other flash storage options on the market.
PCIe Version and its Impact on Performance:
The speed of the SSD will vary depending on the PCIe generation of your system. The Fourth Generation Samsung 980 Pro NVMe SSD, for example, requires a version 4.0 PCIe interface and an M.2 slot with four V4.0 lanes to attain read rates of around 7000 MB/s. The third-generation Samsung 970 EVO NVMe SSD, on the other hand, offers a maximum read speed of 3500 MB/s and requires 4 x V3.0 PCIe lanes.
From here, a few key observations may be made. Installing a Gen 4 M.2 NVMe SSD, such as the Samsung 980 Pro, in an M.2 Slot that conforms to the older PCIe v3.0 standard reduces performance by half. If you put a Gen 3 M.2 NVMe SSD, such as the Samsung 970 EVO, in an M.2 slot that conforms to the newer PCIe v4.0 standard, it will NOT get any performance advantage. Similarly, if the M.2 slot only has two lanes, the speed of the SSDs will be cut in half in all cases. The PCIe generation you have is determined by your CPU and motherboard chipset.
Other Devices that May use PCIe Lanes:
Although this is not a uniform standard, most CPUs offer four more PCIe lanes than claimed. These four additional lanes serve as a high-speed connection to the motherboard chipset.
The chipset divides the available bandwidth across a variety of functions. The specific feature arrangement varies across motherboards, however, all onboard I/O (Input/Output) functions like ethernet, SATA, USB, and audio are included.
Graphics cards are the most common devices that use PCIe lanes; they employ an x16 connection to give up to 16 PCIe lanes. NVMe SSDs can connect utilizing PCIe slots, an M.2, U.2, or DIMM.2 connection, and can utilize up to four PCIe lanes.
Expansion cards, including sound cards, networking cards, USB expansion cards, and raid controllers, also utilize PCIe lanes. When a CPU with just 16 PCIe lanes is equipped with a graphics card and an M.2 SSD, the graphics card’s lanes are reduced to eight, freeing up four lanes for the SSD.
Also, technically speaking, if a certain 3rd Gen NVMe SSD has a maximum speed of 3500 MB/s and utilizes four PCIe v3.0 lanes, it may potentially have the same performance on only two PCIe V4.0 lanes.
So, How Many PCIe Lanes does NVMe M.2 Use?
As previously stated, the maximum number of lanes that an M.2 slot may use at the present is four. 4x PCIe lanes can accommodate the fastest NVMe SSDs available. However, certain motherboards may include M.2 slots that use only two PCIe lanes.
Some motherboards include four lanes for the first M.2 slot, while others only have two. While both will be able to run an NVMe SSD, the second will be half the performance and will drastically limit your installed SSD.
The configuration of the M.2 Slot’s PCIe lane count is determined by the manufacturer as well as several other parameters such as the motherboard chipset and PCIe generation.
Conclusion:
The one final point I’d want to make is that reading the motherboard specs is almost always necessary when determining the PCIe lanes for the M.2 slot, the physical size of SSD it can accommodate, the PCIe version it employs, and the Chipset it employs.
All of these criteria will have a significant impact on the SSD you choose when you go to buy one. However, the quick answer to how many PCIe lanes does an M.2 slot consume is four.
A PCIe NVMe SSD is the fastest form of SSD available. To accommodate larger bandwidths, they make use of the high-speed PCIe bus. Most PCIe NVMe SSDs have a 4x PCIe lane connection, however, understanding what a PCIe lane is can be challenging because the literature on the subject is dispersed and difficult to grasp.
