Different Types Of Solid State Drives (SSD)

Solid-state drive (SSD) has become a very popular and well renowned storage subsystem that features a viable alternative to the widely-used traditional hard disk drive (HDD) which is based in its architecture and functionality on mechanical operations to perform the requested mission. Solid state drive on the other hand is way different although its use purpose is quite the same which is storing data and make them available once required, but with a speed up to 4 times greater than mechanical hard drives.

Types of Solid State Drives

There are a few different types of SSDs available for consumer which they can choose the most suitable for their needs. The first type is an external portable SSD that is made primarily for those who need a flexible external storage device for backup and large file transfers. As with any technology, there are trade-offs, depending on which of the two types of flash SSD you select. Multi-level cell (MLC) flash is most common and is often found in consumer-grade products such as cameras, phones, USB memory sticks and portable music players but is also present in some enterprise storage products.

SSDs have no moving (mechanical) components. This distinguishes them from traditional electromechanical magnetic disks such as hard disk drives (HDDs) or floppy disks, which contain spinning disks and movable read/write heads.[5] Compared with electromechanical disks, SSDs are typically more resistant to physical shock, run silently, have lower access time, and less latency.[6] However, while the price of SSDs has continued to decline over time,[7] consumer-grade SSDs are still roughly six to seven times more expensive per unit of storage than consumer-grade HDDs.

Our featured picture might seem a bit intimidating to most simply because the average consumer isn’t used to seeing, much less buying, anything that shows its circuitry and is not nicely packaged as the SSD in the middle is. It displays the OCZ RevoDrive 3×2 480GB PCIe card on the bottom, followed by the Crucial M4 512GB SATA 3 SSD with the Renice x3 mSATA 120GB SATA 2 SSD on top. A simple click on any of these links will bring you to the analysis we did of each on their release.

Speed Of SSD

The traditional spinning hard drive (HDD) is the basic nonvolatile storage on a computer. That is, it doesn’t “go away” like the data on the system memory when you turn the system off. Hard drives are essentially metal platters with a magnetic coating. The main characteristic of MLC flash is its low price, but it suffers from higher wear rates and lower write performance compared with single-level cell (SLC) technology. An internal hard disk drive (HDD) has the same exact purpose than regular SSDs aiming at consumer-level market. SLC is faster and much more reliable — but also more expensive — and is featured in the best-performing storage arrays. That coating stores your data, whether that data consists of weather reports from the last century, a high-definition copy of the Star Wars trilogy, or your digital music collection. A read/write head on an arm accesses the data while the platters are spinning in a hard drive enclosure.

As of 2014, most SSDs use NAND-based flash memory, which retains data without power. For applications requiring fast access, but not necessarily data persistence after power loss, SSDs may be constructed from random-access memory (RAM). Flash memory — typically NAND flash memory — is found in USB flash drives and all the different types of SD cards you’d buy. USB flash drives contain a flash memory chip on a printed circuit board (PCB) as well as a basic controller and a USB interface. SD cards contain a flash memory chip on a circuit board along with an SD controller. Both SD cards and flash drives aren’t very sophisticated. They don’t have the sophisticated firmware or other advanced features you’d find in an SSD. They’re generally designed to be as cheap as possible. Such devices may employ separate power sources, such as batteries, to maintain data after power loss.

In general, because SLC drives are less complex they have longer MDF, less storage capacity, higher costs and theoretically outperform MLC drives. This however is no longer the case as other factors mainly the design of the controller, and improvements in firmware as well as the NAND flash chips have brought MLC performance to be equal or faster then their SLC counterparts. This is evident in the data center and enterprise markets where MLC drives are rapidly replacing SLC drives because of their better price points, larger storage capacities, and similar performance.

The best option you have

An SSD does much the same job functionally (e.g., saving your data while the system is off, booting your system, etc.) as an HDD, but instead of a magnetic coating on top of platters, the data is stored on interconnected flash memory chips that retain the data even when there’s no power present. The first differentiator for SSD relates to the NAND flash of which would either be SLC (Single Level Cell) or MLC (Multi Level Cell). The difference between the two is the amount of data stored per cell, with SLC it’s 1-bit per cell and with MLC it’s 2-bits per cell. Now even with a solid storage subsystem you’ll not be able to reach the utmost speed of a computer without considering the other speed factors. These differences in design impact performance, MDF, storage capacity, and most importantly price point. The chips can either be permanently installed on the system’s motherboard (like on some small laptops and ultrabooks), on a PCI/PCIe card (in some high-end workstations), or in a box that’s sized, shaped, and wired to slot in for a laptop or desktop’s hard drive (common on everything else). There are a number of different “speed classes” of SD cards — and the slow ones are very slow. You wouldn’t install your operating system on an SD card if possible, as this would be much slower than using a good SSD. These flash memory chips differ from the flash memory in USB thumb drives in the type and speed of the memory. That’s the subject of a totally separate technical treatise, but suffice it to say that the flash memory in SSDs is faster and more reliable than the flash memory in USB thumb drives. SSDs are consequently more expensive than USB thumb drives for the same capacities.