PCIe vs. NVMe

When Solid State Drives (SSD) began to replace spinning hard drives in a major way, the performance differences between the expensive models from major brands and the affordable ones from lesser known manufacturers was substantial. As that gap decreased, the major brands were forced to slash their prices since they no longer had a noticeable performance advantage.

Because they are much more affordable today, SSDs are a worthwhile upgrade for people still using hard drives. SATA (Serial Advanced Technology Attachment) was the SSD standard for years. Generally speaking, a SATA SSD will perform with a maximum sequential read rate of around 600 MB/second and a max write rate of 550 MB/s. In a real-world environment you can expect read and write rate speeds in the 400-500 MB/s range.

Standard 2.5” SATA drives are designed to work on an interface created for mechanical hard drives. This older technology makes SATA drives overly large and slow by today’s measures.

PCIe

PCIe (peripheral component interconnect express) SSDs are much smaller than SATA drives and are completely powered by the connection to the motherboard, which eliminates the two cables you would find in traditional 2.5” SSD drives. SATA drives are slower, but are also cheaper and are compatible with older systems. NVMe (Non-Volatile Memory Express) is a much faster PCIe interface than SATA.

PCIe 1.0 was released in 2003. Most users today are running systems on the 3.0 generation.

NVMe

NVMe 3.0 SSDs can get up to a max of 3,500 MB/s, with real-world rates typically between 1,200-2,400 MB/s. Gen 3.0 has been the standard for several years. It remained the go-to version even as the 4.0 versions were released due to the fact that the newer models did not show a great enough increase in performance on a consistent basis to justify the higher price.

However, the new NVMe 4.0 SSD models are showing true next-generation performance with speeds up to 7,000 MB/s, filling the ever-growing need for faster access to data. This is especially beneficial in gaming, where loading can go directly to the GPU, bypassing the CPU for much faster performance. Additionally, content creators will see major performance improvements in areas such as viewing multiple HD sources simultaneously without dropping frames.

Keep in mind that having an SSD that is constantly writing gigabytes of data is bound to create some serious heat issues. This should not cause any problems if you have a heat spreader or have plenty of airflow in your system. Some of the newer Gen 4.0 NVMe SSDs come with a heatsink, which mitigates any overheating problems.

PCIe slots can be described by the number of lanes they feature. The most common models are one, four, eight and 16 lanes. Higher lane counts mean faster transfer rates and greater overall bandwidth. The number of lanes is usually determined by the function of the expansion card. For example, graphics cards usually require 16 lanes while sound cards only require one.

An advantage of using PCIe as a data highway is that latency is reduced to a negligible 10 microseconds. It also increases the maximum transfer speed to 3 GB/s. The data that NVMe can transfer in one second would take 17 seconds on a traditional mechanical hard drive.

PCIe 5.0 was introduced in 2019, but much like the introduction of 4.0, it is currently very expensive and not compatible with most systems. PCIe 6.0 is expected to be introduced in 2021. All versions of PCIe SSDs interface with an M.2 slot, so expect this connection to remain on motherboards for years to come.

While the benchmark speed for loading and data transfer get impressively faster with each iteration, some say that the SSD upgrade may be approaching the point of diminishing returns. The test speed might be fast, but in a practical gaming or video editing or workstation situation, determining whether the performance increase is worth it, or in some cases whether it is even noticeable, will have to be decided by individual users. An enthusiast who uses their computer for standard applications such as games and music files may not be as likely to need an upgrade as a superuser, like a network administrator might.

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