Which SSD technology is the fastest?

NVMe drives are a big deal in computer storage right now, and for good reason. Not only does an NVMe SSD leave most older SSDs in the dust, it's also blazingly fast compared to standard 3,5-inch and 2,5-inch drives.

NVMe vs. SATA III

Take, for example, the Samsung 860 Pro 1TB, a 2,5-inch SSD with a maximum sequential read speed of 560 megabytes per second (MB / s). Its successor, the NVMe-based 960 Pro, is more than six times faster than that, with a top speed of 3MB / s.

This is because pre-NVMe drives connect to a PC via SATA III, the third revision of the Serial ATA computer bus interface. NVMe, on the other hand, is the host controller interface for newer and more advanced SSDs.

SATA III and NVMe are the terms most commonly used to tell the difference between old-school drives and the new heat that everyone wants. NVMe, however, is not the same type of technology as SATA III.

We'll see why we use the terms "SATA III" and "NVMe" to compare technologies later.

What is SATA III?

In 2000, SATA was introduced to replace the predecessor Parallel ATA standard. SATA offered faster connections, which meant significantly improved performance over its predecessor. SATA III was deployed eight years later with a maximum transfer rate of 600MB / s.

SATA III components use a specific type of connector to fit into a laptop computer and a specific type of cable to connect to a desktop PC motherboard.

Once a drive is connected to the computer system via SATA III, the job is only half done. In order for the reader to actually talk to the system, it needs a host controller interface. This work belongs to AHCI, which is the most common way for SATA III drives to communicate with a computer system.

For many years, SATA III and AHCI performed admirably, including the early days of SSDs. However, AHCI has been optimized for high latency rotating media, and not for low latency nonvolatile storage like SSDs, a representative from the drive maker Kingston explained.

SSDs got so fast that they eventually saturated the SATA III connection. SATA III and AHCI simply could not provide enough bandwidth for increasingly better SSDS.

With the increase in speeds and training capabilities, the search was underway for a better alternative. And, luckily, it was already in use on PC.

What is PCIe?

PCIe is another hardware interface. It's best known as the way a graphics card fits into a desktop PC, but it's also used for sound cards, Thunderbolt expansion cards, and M.2 drives (more on this later).

If you look at a motherboard (see above), you can easily see where the PCIe slots are. They mainly come in x16, x8, x4 and x1 variants. These figures indicate the number of data transmission channels in a slot. The higher the number of lanes, the more data you can move at any time, which is why graphics cards use x16 slots.

There is also an M.2 slot in the image above, just below the top x16 slot. M.2 slots can use up to four lanes, so they are x4.

The key PCIe slots on any computer have lanes connected to the processor for the best possible performance. The rest of the PCIe slots connect to the chipset. This also supports a fairly fast connection to the processor, but not as fast as direct connections.

Currently, there are two generations of PCIe in use: 3.0 (the most common) and 4.0. As of mid-2019, PCIe 4.0 was brand new and was only supported on AMD Ryzen 3000 processors and X570 motherboards. Version 4, as you might expect, is faster.

However, most components do not yet fill the maximum bandwidth of PCIe 3.0. So while PCIe 4.0 is impressive, it is not yet a necessity for modern computers.

NVMe on PCIe

PCIe is therefore like SATA III; they are both used to connect individual components to a computer system. Just as SATA III needs AHCI before a hard drive or SSD can communicate with a computer system, PCIe drives rely on a host controller, called express non-volatile memory (NVMe).

But why aren't we talking about SATA III drives vs. PCIe, or AHCI vs. NVMe?

The reason is quite simple. We've always considered drives to be SATA-based, like SATA, SATA II, and SATA III - no surprise there.

When drive manufacturers started making PCIe drives, we talked briefly about PCIe SSDs.

However, the industry did not have standards to rally around like it did with SATA drives. Instead, as Western Digital explained, companies used AHCI and built their own pilotes and firmware to run these disks.

It was a mess, and the AHCI still wasn't good enough. As Kingston explained to us, it was also more difficult for people to adopt faster drives than SATA because, rather than a plug-and-play experience, they also had to install drives that were faster than SATA.iloyour specials.

Eventually, the industry rallied around the standard which became NVMe and replaced AHCI. The new standard was so much better that it made sense to start talking about NVMe. And the rest, as they say, is history.

NVMe was designed with modern PCIe-based SSDs in mind. NVMe drives can take many more commands at a time than mechanical hard drives or SATA III SSDs. This, combined with lower latency, makes NVMe drives faster and more responsive.

What do NVMe drives look like?

If you're shopping today for an NVMe-based player, what you want is an M.2 gumstick. M.2 describes the form factor of the player or, for our purposes, how it looks. M.2 drives typically have up to 1TB of storage, but they're small enough to fit between your thumb and forefinger.

M.2 drives connect to special M.2 PCIe slots that support up to four lanes of data transfer. These drives are usually NVMe based, but you can also find M.2 drives that use SATA III - just read the packaging carefully.

M.2 based on SATA III is not that common these days, but it does exist. Some popular examples are the WD Blue 3D NAND and the Samsung 860 Evo.

Should you empty SATA III drives?

While NVMe is fantastic, there's no reason to ditch SATA III drives just yet. Despite the limitations of SATA III, it's still a good choice for secondary storage.

Anyone building a new PC, for example, would do well to use an M.2 NVMe drive for their boot drive and primary storage. It could then add a cheaper hard drive or 2,5 inch SSD with more secondary storage capacity.

It might be a good idea to have all of your storage running on PCIe. However, currently NVMe drives are limited to around 2TB. Higher capacities are also prohibitively expensive. A budget 2TB M.1 NVMe drive typically costs around $ 100 (which costs around a 2TB high performance SATA III hard drive).

The price, of course, can change as we get even higher capacity M.2 drives. Kingston said we can expect to see M.2 drives with 4TB and 8TB capacities sometime in early 2021.

Until then, combining M.2 with SSDs and secondary hard drives is the best option.

The same idea applies to laptops. If you're buying a new platform, look for one with NVMe flash storage and a spare 2,5-inch bay for a SATA III hard drive or SSD.

However, not all NVMe drives are created equal. It certainly pays off to read the reviews on your target reader before purchasing one.

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If you have a newer desktop or laptop, chances are it has M.2 slots that support NVMe. Upgrading your PC is worth it!