2 Types of M.2 SSDs: SATA and NVMe

When we talk about M.2 in storage technology, we’re usually talking about an SSD by referring to its form factor. M.2 refers to an SSD form factor that resembles a stick of chewing gum. Its small and slim size makes it ideal for computers that are lightweight and portable like laptops, notebooks, NUCs and ultrabooks. They take up less room than 2.5-inch SSDs or hard drives and can go up to 2TB in capacity.

Now that we’ve explained what M.2 is, let’s address the question, “Is M.2 faster than an SSD?”

The answer is no. M.2 is a form factor of SSDs so that question doesn’t really make sense. Still, the underlying confusion behind the question is understandable since M.2 SSDs are relatively new when compared to the other form factors of client SSDs. There are two types of M.2 SSDs, which are SATA and NVMe-based. They differ in storage technology and, depending on your needs and budget, they each have their individual pros and cons.

SATA M.2 SSD

Let's start by saying that in December 2022 we shipped out the last of our SATA M.2 SSDs, the A400 M.2. We no longer make SATA-based M.2 SSDs and, going forward, all our M.2 SSDs are NVMe. But at the time, SATA M.2 SSDs used the SATA interface with a maximum data transfer rate of 6Gbps. This is slow compared to newer interfaces (more on that below). SATA-based SSDs are the lowest grade of SSDs in terms of performance and use the same interface as hard drives. Still, SATA-based SSDs have three to four times the bandwidth compared to spinning disk hard drives. SATA SSDs were more available and affordable than NVMe SSDs. SATA M.2 SSDs were a great alternative to a 2.5-inch SSD if you didn’t have room for a 2.5-inch SSD in your computer.  An M.2 SSD that has both an M key and a B key, as pictured, will be a SATA SSD.

SATA had been the primary interface used for storage technology for a long time. SATA drives needed two cables to work. One is used to transfer data to the motherboard and the other to get power to the PSU (power supply unit). Cable clutter is one of the issues that can affect performance in PC cases when using multiple SATA storage drives. Slim notebooks and laptops, including ultrabooks, don’t even have room for SATA cables, which is why they utilise the M.2 form factor. A SATA M.2 form factor SSD solved this problem since it didn't have the two cable connections previously used in other SATA-based storage drives.

Still, just because it’s an M.2 SSD doesn’t change the fact that it’s a SATA SSD. The main differences between a SATA and NVMe M.2 SSD are the interface technology and levels of performance. A SATA M.2 SSD still uses SATA-based interface technology, which doesn’t improve its speed and performance compared to an NVMe M.2 SSD.

NVMe M.2 SSD

An M.2 SSD that has only the M key, as pictured, will be an NVMe SSD.  NVMe M.2 SSDs utilise the NVMe protocol that was specifically designed for SSDs. When paired with the PCIe bus, an NVMe SSD offers the latest levels of performance and speed. NVMe SSDs communicate directly with the system CPU using the PCIe sockets. Essentially, this allows flash memory to operate as an SSD directly through the PCIe sockets rather than having to use the SATA communication driver, which is a lot slower than NVMe.

NVMe M.2 SSDs are much more performance driven compared to SATA M.2 SSDs. By leveraging the PCIe bus, NVMe M.2 SSDs have theoretical transfer speeds of up to 20Gbps, which is already faster than SATA M.2 SSDs with 6Gbps. PCIe buses can support 1x, 4x, 8x and 16x lanes. PCIe 3.0 has an effective transfer speed of up to 985 MB/s per lane, which means there is a potential transfer speed of up to 16GB/s. However, there’s only x2 and x4 lanes accessible when using a M.2 form factor with the PCIe bus, which translates to a maximum transfer speed of up to 4GB/s.

Is NVMe faster than SATA? Technically, yes. Modern motherboards use SATA III which has a max throughput of 600MB/s while NVMe drives provide speeds up to 3,500MB/s. The level of performance is much greater than SATA SSDs, regardless of form factor. Only SSDs that utilise NVMe technology exceed the transfer speed caps that limit the SATA-based SSDs.

When deciding between a SATA M.2 SSD or an NVMe M.2 SSD, here are some things to consider:

• System support - Older devices may not be compatible with NVMe as they don’t have the necessary connections to utilise the NVMe PCIe sockets.
• Quick start-up – The easiest way to make your computer system boot faster is to install the OS (operating system) on an SSD. You’ll see the greatest speed improvements with an NVMe SSD.
• Prioritise storage – You can use an NVMe SSD in combination with another SATA SSD. This is an affordable option without having to break the bank. You can install your OS and resource-intensive programs and applications on the NVMe SSD and use the SATA SSD to store everything else, like the smaller and less resource-hungry files, docs, etc.
• Gaming advantages – You’ll see a drastic improvement in gaming load times when using an M.2 NVMe SSD. Games installed on NVMe drives will have vastly better performance overall because of the transfer speeds when recalling your games from storage.
• PCIe generations – There are generations of the PCIe bus that have different levels of performance. The bandwidth doubles with each generation and there are SSDs utilising different generations of PCIe. The latest available is PCIe 4.0, with PCIe 5.0 still on the development horizon.
• Shared connections – Some motherboards don’t have enough PCIe connections to support multiple NVMe drives. You might have to decide on using the available connection between a graphics card or an NVMe SSD. Other times, there may be PCIe lanes available but only a certain type of connection will be able to use NVMe devices at their full speed, such as an M.2 connection.