M.2 vs NVMe vs. 2.5" vs. U.2 SSDS (2024)

Description:NVMe stands for Non-volatile Memory Express, characterized by high bandwidth and very fast transfer speeds. “Non-volatile” memory indicates that being powered is not a requirement for this device to retain stored information.

To contrast, RAM or DRAM is “volatile” memory storage so once power is cut, the data is lost.

Read/write speeds of the top NVMe SSDs on the market can exceed 3000 MB/s (3 GB/s), with some Gen 4 NVMe PCIe SSDs capable of 7500 MB/s. The top SATA SSDs clock in around 550 MB/s, so NVMe SSDs are far and away the fastest transfer speeds for any SSDs on the consumer market.

You may see reference to “lanes” when purchasing M.2 NVMe SSDs. Basically, more lanes equals both a longer SSD and faster transfer speeds, with one lane equal to about 1 GB of transfer speed. A 4 lane NVMe SSD will have twice the bandwidth than a 2 lane NVMe SSD. Most 4 lane M.2 NVMe SSDs have one key, unlike the M.2 SATA SSDs which have two.

However (confusingly), some 2 lane M.2 NVMe SSDs have two keys, just like M.2 SATA SSDs. Be sure to carefully read the product description before purchasing either since this could impact your ability to connect the SSD to your motherboard. Also, check the transfer speeds—if speeds exceed 550MB/s, you’re looking at an M.2 NVMe SSD and not a M.2 SATA SSD.

Advantages: M.2 NVMe SSDs have the clear transfer speed advantage. They’re also smaller than 2.5” SATA SSDs due to the M.2 form factor.

Due to the PCIe connection protocol, M.2 NVMe SSDs are backward and forward compatible, so you can use PCIe 3.0 NVMe SSDs with a PCIe 2.0 system or vice-versa. However, using a PCIe 3.0 SSD with a PCIe 2.0 motherboard will reduce overall bandwidth availability. On the other hand, using a PCIe 2.0 SSD with a PCIe 3.0 motherboard will not throttle performance.

Disadvantages: The faster the drive, the more expensive. M.2 NVMe SSDs cost more than either 2.5” SSDs or M.2 SATA SSDs. Also, while motherboards may be compatible with the M.2 form factor, they may not support NVMe. Make sure to read your motherboard specs carefully before making your purchase.

Reportedly, M.2 NVMe SSDs also run hot since they’re transferring so much data so quickly. If you don’t have a solid cooling solution for your computer, you may want to install or upgrade your heat sinks before installing M.2 NVMe SSDs.

Also, not everyone needs this kind of speed! If you’re not a hardcore gamer running the latest titles with graphically rich detail and you can patiently wait for your computer to boot up, you could save a bit with a SATA SSD and have an easier time installing it if you’re upgrading your current system.