In this article I will explain the main differences between four storage types you can find in modern Windows-based desktops and laptops – hard disk drives (HDD), hybrids (HHDD / SSHD), solid state drives (SSD) and M.2 NVMe storage.
Hard Disk Drive Storage (HDD)
Hard disk drives or HDDs are the traditional storage devices for personal computers. You can find them in the majority of notebooks, especially inexpensive ones. These are hard drives are based on rotating magnetic platters and reading heads. HDDs are the slowest kind of storage in modern PCs. In today’s era of fast processors and large system memory amounts, these hard drives are oftentimes your system performance bottleneck. On the positive side, HDD is the cheapest kind of storage.
Solid State Drive (SSD) Storage
Solid state drive-based storage is newer technology than the decades old hard drive storage (HDD). SSDs have no moving parts, since data is stored on Flash memory-based modules. Performance of different SSD models varies, but most SSDs on the market are significantly faster then HDD. Other advantages of solid state storage versus hard drives are completely silent operation, lower power consumption which allows longer battery life, open applications almost instantly and lower chances of data loss due to accidental drops
On the negative side, common capacities of solid state drives are generally smaller than capacities of mechanical hard drives (HDD). SSDs vary between 128 GB and 1 Terabyte and have a noticeably higher price per Gigabyte than hard drives. The sweet spot now a days would be a 500GB SSD.
Hybrid Hard Drive / Solid State Drive Storage (HHDD or SSHD)
Hybrid hard disk drives (HHDD), also known as solid state hybrid drives (SSHDs), combine hard drive and solid state storage in a single 2.5″ device. They aren’t as widely adopted as pure HDDs and SSDs. Hybrid drives have all parts you can find in a classic HDD and include an SSD module on top of them. It’s hard to compare raw performance of HHDDs / SSHDs to HDDs, SSDs, because hybrids don’t load every stored file and installed program at a same speed. They boost loading only of software and files selected by their caching algorithms, based on your common computer usage scenarios. Software and files you most frequently use, including those required for booting up the operating system itself, are stored on the SSD portion for faster loading. Accessing the rest of the data stored on the HDD portion isn’t quicker than on comparable pure HDDs.
Common capacities of laptop-use hybrid storage devices are 500GB and 1TB on the hard disk platters, plus either 8GB, 16GB or 32GB of SSD memory.
M.2 PCI Express NVMe Storage
For comparison’s sake between SSD vs M.2 PCI Express (PCIe) SSD, PCI Express is more like a SSD on steroids. In a theoretical mad dash to the finish line, an M.2 PCI Express SSD leaves an SSD in the dust. Compare and contrast theoretical PCI Express bandwidth in the excess of 20Gb/s to SATA III which is capped at 6Gb/s for regular SSD’s. But even so, it’s not so cut and dry as it seems. Let me explain.
NVMe or Non-Volatile Memory Express is a nextgen high-performance command protocol which supercedes AHCI. It overcomes the bottlenecks inherent in AHCI drivers which were built for HDDs and IDE. NVMe is expressly built from the ground up to cater to NAND Flash-based SSDs, unlike AHCI. It offers better throughput, reduced latency and low power consumption compared to SSDs.
Let’s clarify on something though, NVMe is not a physical connection interface like SATA or PCIe. NVMe runs on top of PCIe SSDs such as M.2 or PCI-Express SSDs improving performance by as much as 5 times that of its SATA hard drive counterparts.
This storage is slightly more expensive than SSD hard drives however not all computers have the capability to run m.2 NVMe due to the lack of the port internally. SSD is uses the universal Sata standard port like HDD and SSHD uses. Simplest way to make sure you have M.2 NVMe is to purchase a new computer with this type of storage already in use.