Solid state drives (SSDs) are much faster than traditional hard disk drives (HDDs), allowing computers to boot up, run applications and transfer files significantly faster. Similarly, in data centers, SSDs enable servers to store and access data more quickly, speeding data-intensive workloads like data analytics and online transactions. PCIe, which is a high-speed computer expansion bus, enables SSDs to go even faster.

PCIe, which stands for peripheral component interconnect express, is an interface that connects peripheral components such as storage, graphics cards and memory to the motherboard.

Most mainstream desktop and laptop computers and servers sold today support PCIe Gen 4 or 4.0 SSDs, which is the fourth generation of PCIe and doubles the data transfer rates of PCIe 3.0 SSDs. Meanwhile, next-generation PCIe 5.0 SSDs are just coming onto the market, but they double the data transfer speeds of Gen 4 and quadruple the throughput of Gen 3.

Samsung’s portfolio of SSDs supports these three current generations of PCIe, providing businesses and consumers with the fastest available storage for their existing and future hardware. Let’s take a deeper look at PCIe Gen 4 SSDs and how they compare with SSDs that support the previous and next-generation PCIe standards.

PCIe Gen 4 vs. PCIe Gen 3 and Gen 5: What’s the difference?

Computers and servers that support PCIe Gen 3 and Gen 4 now dominate the hardware landscape. Today, a huge installed base still uses SSDs that support PCIe 3.0, a standard that was launched in 2010, and the older SATA interface. But with PCIe Gen 5 still emerging, the fastest computers and servers available today primarily support PCIe 4.0, which became a standard in 2017.

The biggest difference in the PCIe versions is the data transfer rates. Each new version of PCIe doubles the speed of the previous version. For example, PCIe slots come in five configurations in a motherboard: x1, x2, x4, x8 and x16, which represent the number of lanes available.

PCIe 3.0’s data transfer rate is 1GB per lane. PCIe 4.0 doubles the throughput to 2GB per lane, while PCIe 5.0 doubles the data transfer rate again to 4GB per lane.

That means, a PCIe 4.0 x4 SSD, which uses four lanes, will offer nearly 8GB/s of theoretical throughput, which is twice the bandwidth of PCIe 3.0 and half the bandwidth of PCIe 5.0.

To put it another way, PCIe 3.0 delivers 8 gigatransfers per second (GT/s) raw bit rate. PCIe 4.0 doubles that to 16GT/s, and PCIe 5.0 doubles it again to 32GT/s.

Why PCIe with NVMe® is better than SATA SSDs

PCIe, paired with a communications protocol called NVMe, enables blazing fast SSD speeds and eliminates performance bottlenecks experienced with the SATA interface, which was originally designed for HDDs and hampered SSD performance. In contrast, NVMe, which stands for non-volatile memory express, is a transport protocol that’s purpose-built to allow fast data transfer rates on PCIe SSDs.

PCIe-based NVMe SSDs also reduce latency and enable higher input/output operations per second (IOPS), which is perfect for databases and other data-intensive, compute-intensive and graphics-heavy applications.

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Real-world examples: Samsung’s PCIe NVMe Gen 4 and Gen 3 SSDs

Samsung’s PCIe NVMe Gen 4 SSDs are twice as fast as Gen 3 SSDs. For example, the Samsung 990 PRO, an internal PCIe 4.0 x4 SSD for PCs, features sequential read/write speeds of 7,450/6,900 MB/s, which is 2.1 times faster than a PCI 3.0 SSD and 13.3 times faster than a SATA SSD. Samsung offers a version of the 990 PRO with Heatsink technology, which dissipates heat to prevent performance drops from overheating.

Similarly, the Samsung 980 PRO PCIe 4.0 NVMe SSD for PCs offers sequential read/write speeds of 7,000/5,000 MB/s, which is about twice as fast as the prior SSD 980 PCIe 3.0 NVMe version, which reaches sequential read/write speeds of 3,500/3,000 MB/s.

For data center operators, the Samsung PM9A3 PCIe 4.0 x4 SSD delivers sequential read/write speeds of 6,900/4,100 MB/s and random read/write speeds of 1,000K/180K IOPS. The PM9A3 SSD more than doubles the speeds of its predecessor, the PM983 PCIe 3.0 x4 SSD.

PCIe Gen 5 SSDs are the future

Hardware makers have begun shipping their first desktop PCs and servers with next-generation chips and PCIe 5.0 motherboards. PCIe Gen 5 SSDs are also making their way to the marketplace.

For example, the Samsung PM1743 PCIe 5.0 SSD for high-performance servers is twice as fast as PCIe 4.0 SSDs, hitting sequential read/write speeds of 13,000/6,600 MB/s and random read/write speeds of 2,500K/250K IOPS. The SSD, designed for AI and other data-intensive, mission-critical applications, is also 30% more energy efficient than Samsung’s previous generation SSDs.

There are some challenges to PCIe 5.0 SSD adoption, however. Laptops with PCIe Gen 5 SSDs are not yet available because the blazing-fast storage drives produce too much heat and consume too much power, according to Tom’s Hardware. This issue is getting resolved, though, because notebook vendors expect to start selling laptops with PCIe Gen 5 SSDs by late 2024, the article said.

For example, in January, Samsung introduced its first PCIe Gen 5 NVMe SSD for consumers, including a version for ultra-thin laptops.

The new Samsung 990 EVO — designed for everyday needs from gaming, business use and content creation — can operate in two modes : PCIe 4 x4 and PCIe 5 x2. While connected to a Gen 5 interface, it operates on two lanes, which solves the thermal issues facing laptops.

The 990 EVO reaches sequential read/write speeds of 5,000/4,200 MB/s, which provides 43% faster sequential reads and 30% faster sequential writes compared to the previous generation 970 EVO Plus. It will also be 70% more energy efficient than the previous version.

To recap, PCIe 4.0 NVMe SSDs have accelerated computer and server performance dramatically. And when consumers and businesses are ready to upgrade, PCIe 5.0 NVMe will boost speeds even more.

Samsung offers a large portfolio of consumer, enterprise and data center SSDs that support all the current PCIe standards, from Gen 3 and Gen 4 to Gen 5.

Learn more about how Samsung SSDs can level up storage and performance. And browse Samsung’s acclaimed SSD offerings for the right size and form factor for your organization.

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Wylie Wong

Wylie Wong is a journalist and freelance writer specializing in technology, business and sports. He previously worked at CNET, Computerworld and CRN, and loves covering and learning about the advances and ever-changing dynamics of the technology industry.

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