1. Drive Performance
While clients may focus on SSD throughput, more commonly presented as read/write rate, as the key factor in determining drive performance, it is of primary concern when transferring a large amount of data on or off the drive. In comparison, input/output operations per second (IOPS) is the measure of performance, so when comparing SSDs, put a higher priority on IOPS than on read/write rates, as high IOPS has more of a performance impact.
While SSD capacity depends largely on the usage scenario, it generally ranges from 120 or 128 GB at the low end all the way to 800 GB or more for most business needs. Despite the recent swell of options in the range of 1 TB and higher, they are primarily for data centers and other enterprise applications. The introduction of 3D NAND flash technology is the driver of these larger capacities which has been explored as gaining ground in 2016 is the technology chiefly responsible for these higher capacities.
All consumer SSDs make use of one or two flavors of the Serial ATA (SATA) interface. The standard for the last few years has been 6 Gbps SATA (a.k.a. "SATA 3.0"), which allows for greater throughput. The drive and computer must both support 6 Gbps SATA in order to see the speed benefit, but 6 Gbps drives are also backward-compatible.
The best SSD for you may depend on price and capacity, but 6 Gbps drives are pretty much all you'll see today in mainstream SSDs. Six Gbps is plenty quick for most desktop and gaming applications and will keep your boot times in the sub-five-second range if you’re running a fresh operating system straight off the disk.
Peripheral Component Interconnect Express (PCIe) makes production of SSD technology 2 TB and higher easier while allowing triple the read/write performance throughput of standard SATA SSD. While PCIe SSDs are a natural fit for enterprise and server applications, they may be overkill for average desktop use. In addition, NVMe technology is making major speed-transfer improvements and removing the overhead mandated by SATA, but support for it on desktop motherboards and in laptops is still limited.
4. Size and Thickness
SSD comparison when it comes to size and thickness goes to the device in which the client will use the SSD. Most SSDs come in a 2.5-inch-wide standard form factor that conforms to the drive bay in a laptop. In a desktop, you may need a 2.5-inch-to-3.5-inch bay adapter in order to install an SSD in a standard hard-drive bay.
Today, the thickness, or “Z-height,” of an SSD has moved to 7 mm in order to accommodate ultrathin laptops. In addition, the newer SSD standard called “M.2” also comprises small-form modules that fit well in thin laptops and space-constrained mini-PCs.
Every SSD features a controller chip that manages data on the memory cells and communicates the other components on the computer, such as the motherboard and other data storage devices. The controller is the silicon on the SSD that traffics data between your PC’s SATA interface and the NAND chips on the SSD.
Memory controllers handle many prominent features found in SSDs, such as wear-leveling, reading data, writing data, and data-provisioning. Because of that, the type of memory controller used (controllers can have four or eight channels) can impact drive performance, reliability, endurance, and other extraneous features. Although an SSD’s controller is one of the bigger differentiating factors between brands and models, some vendors of SSDs use the same controllers, while a few other SSD makers design or customize their own controllers.
6. Enterprise Versus Consumer-Grade SSD
Enterprise drives are meant to be on 24/7 and can usually withstand higher temperatures or other stresses. Consumer-grade drives are expected to be on eight to 10 hours a day, so life span and mean time between failures are based on these expectations.
Enterprise drives are supported by firmware that enables intelligent wear-leveling, better error-checking, and “smarter” firmware in general. Enterprise drives may also have a larger capacity of spare overhead in order to deal with failed blocks. Consumer-grade drives will have a stripped-down or more basic firmware.
In terms of components and construction, enterprise drives will usually be made of longer-lasting flash memory and will use different architectures that may be constructed to optimize performance in specific workloads, while consumer-grade drives don’t necessarily require this level of component architecture.
Although all of these factors will weigh into the decisions when it comes to SSD comparison, having a command of these facts will only get the client so far. The reality is that the VAR’s knowledge of the client and the client’s needs will shape how the VAR advises and recommends SSDs that will meet those needs.