For a long time the traditional method for a storage device for both desktops and laptops has been the mechanical hard disk drive (HDD). This type of storage consists of moving parts and has the feature of low costs combined with a very large storage capacity. However, the mechanical nature of such storage gives rise to slow data speeds and a high vulnerability (risk) to vibration, heat and early mechanical failure.
The emergence of the Solid State Hard Drive
The Solid State Drive (SSD) is a relatively new consumer storage solution that has been replacing the majority of mechanical hard disk drives (HDD). Today, SSD has shown to be much more reliable, affordable and to offer a much higher performance.
The very first SSD’s were very expensive and the storage capacity was small. Today, you can (typically) buy a good quality SSD replacement drive with a reasonable size storage of say 512Gb for about $165.00 AUD. Reference unit is a Intel 545s Series 2.5″ 512GB SSD SATA3 6Gbps unit.
What is a SSD?
A SSD is a Solid State Drive using flash memory (metal-oxide semiconductor with a floating gate) to persistently store data as an electrical charge. SSDs can continue to store data even when there is no power supplied over a reasonably long period (a non-volatile storage). As the data is stored in the form of electrical charges, it will start to leak away if no power is supplied for a long period of time.
Traditional HDD to modern SSD comparison
- A SSD can achieve access speeds of 25 to 100 microseconds, which is typically 100 times faster than the traditional HDD
- A typical modern HDD has a access speed between 3,000 to 10,000 microseconds
- A SSD costs more than the same size HDD equivalent. Though this price ratio is dropping with time
- Reliability: A SSD has no moving parts. Flash memory is used to store data
- The traditional HDD has moving parts and consists of a number of magnetic platters spinning at a very high speed (up to 15,000 RPM). Mechanical wear and read / write head crashes are common with HDD
- Power: A SSD uses less power than a HDD, which is very ideal for mobile devices such as laptops where a longer battery run time is required
- Size: SSD is available in a number of format sizes from 1″ to 2.5″ thus increasing the available space in a mobile computer such as a laptop
- Sensitivity: SSD is not affected by magnetism. HDD is effected by external magnetic fields
- Temperature: SSD’s can operate in temperatures from -10 to 70 ℃. A HDD can only operate between 5 to 55 ℃. Industry rated SSD’s can work well from -40~85℃
- Vibration: SSD is not effected by mechanical vibration. A HDD can be crashed (destroyed) by vibration while it is in use and a knock or shock occurs. Failure rates for typical HDD’s are about 4-6% over a expected life span of a several years
- SSDs exhibit a typical failure rate of less a few tenths of a percent over a typical life span
- Weight: SSD’s are much more lightweight than HDD’s
- Fragmentation: Disk fragmentation does not effect reading time on a SSD (seek time is not relevant to where the data storage is positioned)
I have seen cases where changing a laptop from using a HDD to a good quality SSD (typically an Intel device) has given a boot time of 2.5 seconds to Windows 10 being ready for use. On Mac’s, I have seen a similar boot time improvement.
Most new, high-end M.2 SSD drives, support what is known as PCI Express Gen 3.0 x4, paired with a technology called Non-Volatile Memory Express (NVMe) to propel performance dramatically, particuarly with heavy, deeply queued workloads. However, the use of such NVMe M.2 SSD devices requires a very recent hardware support (began about 2017) and boot support in the BIOS.
Most newer motherboards based around Intel’s latest chipsets (such as the Z170, Z270, and Z370, along with their lower-end kin in each generation) will support PCI Express x4 NVMe M.2 SSD drives.
Windows 10 & SSD: Windows 10 is smart how it treats a SSD and will automatically optimise its operations for the best use of solid-state drives. The intention is to maximize SSD performance and achieve a long life.
The Disadvantages of a SSD
Consumer level SSD’s are still more expensive than the consumer level HDD’s (this is improving with time).
Due to the nature of the non-volatile memory chips in a SSD, the device has a limited number of write cycles (up to 5,000,000 times), there are only so many times you can erase and rewrite data on a solid state drive. However, for most users this is within the normal life span of the host computer device (about ~7-10 years).
Data recovery on a faulty SSD can a difficult challenge. Samsung SSDs are one of the most challenging SSD’s simply because most of them have encrypted on-board controllers. So if the controller fails, data recovery is impossible.
TRIM Command: Modern SSD’s use a TRIM command technology that dynamically optimizes the critical life read/write cycles to a reasonable time window. Basically, TRIM enables an operating system to inform a NAND based SSD which data blocks it can erase because they are no longer in use. The use of TRIM can improve the performance of writing data to SSD and contribute to longer SSD life.
Over-Provisioning: Over-provisioned (OP) space is dedicated on a SSD for controller functions like garbage collection and TRIM. A high Over-provisioned amount can lead to less drive degradation and a extended life-span. OP can be set for various workloads to say 7%, 14%, 28%, 50% or more in order to optimize performance, endurance and cost.
Wear Levelling: Wear levelling is used to avoid overusing certain blocks. Frequently writing to or erasing the same blocks leads to wearing out the SSD. A RAM register on the SSD flash controller records the erase count of all blocks to identify which ones are most frequently or least seldom used. Data in frequently used blocks are then swapped to the seldom-used blocks to even out the erase count and effectively smooth the wear level of the SSD device.
Fragmentation: De-fragmentation can prove to be harmful for an SSD lifespan because of its unnecessary write and delete processes. Basically, de-fragmentation is no longer useful for an SSD device as seek time is not relevant to where the data storage is positioned.
The different formats of a SSD
There are SSD’s that use traditional SATA III ports, which means they can be easily swapped to replace an older existing SATA HDD. However, the traditional data throughput of the SATA III connection limits the SSD data speed to 600Mb/s (after a communications overhead). Today, there are many newer SSD’s that also come in a smaller format and use a much faster interface than a traditional SATA (see other SSD formats below).
This type of SSD incorporates a SATA 3.0 interface with a transfer rate up to 6.0 Gbit/s. This older format is now pre-dated and not so common in new computer devices.
PCI Express (PCIe)
This type of SSD incorporates a PCIe 3.0 ×4 interface and can offer a transfer rate up to 31.5 Gbit/s (using NVMe – see below)
This format of SSD has two variants. One uses SATA 3.0 logical device interface and provides a data transfer rate up to 6.0 Gbit/s. The other M.2 variant, uses PCIe 3.0 ×4 interface, typically uses NVMe (see below), and can achieve a transfer rate up to 31.5 Gbit/s. M.2 format SSD’s are usually the smallest SSD’s in term of physical size.
U.2 was developed for the enterprise SSD market and designed to be used with new high performance PCI Express SSD drives along with SAS and SATA drives. U.2 allows hot-swapping of drives, including dual porting for high availability and high performance. U.2 uses the PCIe 3.0 X4 interface just like M.2, the main difference is that the capacity for these high-performance SSDs is not limited by a small circuit board size, so there is more space for more flash-memory chips and thus a higher capacity SSD.
NVMe Protocol (M.2 & PCIe form)
One of the newest innovations in storage technology is the NVMe protocol. New high-performance M.2 drives, now support PCI Express Gen 3.0 x4, paired with Non-Volatile Memory Express (NVMe) to propel performance even further, especially with heavy, deeply queued workloads. Only relatively new computer devices support this format.
Note: NVMe drives can come in both M.2 or PCIe card form factors.
The Future of Storage & Upgrading
If you have a computer with a traditional SATA hard drive, you will see a large performance increase by migrating to a SSD. The cost of good quality SDD’s (I recommended Intel) is now dropping to an acceptable ratio comparing to traditional HDD’s.
Older computers will typically have a SATA III connection which will offer a read / write throughput of up to 600MB/s using a SATA III type SSD.
By comparison, a 7200 RPM SATA (HDD) drive will offer a read / write throughput of about 100MB/s depending on age, condition, and level of fragmentation.
For the most recent and newer computer devices the option to use NVMe SSD’s will provide up to 8 times the speed of a SATA SSD. Older computers will not support NVMe (lack of boot support).
Optionally, on a older computer, you could add a PCI Express/NVMe SSD drive to a desktop computer by the use of using a M.2 drive on a “carrier card” that slots into a existing PCI Express slot of at least four lanes.
Using such a device, an M.2 drive on a PCI Express expansion card lets you tap the great speed of PCI Express/NVMe without having a supporting M.2 slot. The card may also add boot support, so check that out.
Regardless of using SSD or HDD a good backup plan is still essential as for different reasons eventually any drive will fail.