SATA and M.2 Solid-State Drive FAQs

SSD is short for solid-state drive. An SSD is built using NAND Flash or DRAM memory chips in place of platters and other mechanical mechanisms found in hard disk drives (HDDs).

This is a difficult question to answer, as no two systems are the same and performance can be affected by the OS, any drivers loaded, applications in use, the speed and configuration of the processor and many other factors. There are several test web sites and magazines that have tested SSDs against HDDs and found SSDs to be much faster. For example, if we compared random read performance, SSDs are more than 20000% faster than high performance HDDs.

It is worth noting that SSD drives are not affected by the physical limitations of hard drives. HDDs platters are circular in design (like a CD) and data held at the center of the circle is accessed at a slower rate than data on the outside edge. SSDs have a uniform access time across the entire drive. HDD performance also suffers from data fragmentation, while SSD performance is not significantly impacted even if the data is not stored contiguously.

IOPS (Input/output Operations per Second) is the unit of measurement to show the number of transactions per second a storage device (HDD or SSD) is capable of handling. IOPS should not be confused with read/write speeds and pertain to server workloads.

SSD drives use NAND Flash memory as the storage medium. One of the disadvantages of NAND Flash is that Flash cells will eventually wear out. To extend the memory’s useable life, the SSD’s memory controller employs various algorithms that spread the storage of data across all memory cells. This prevents any one cell or group of cells from being “over used.” The use of wear-levelling technology is widespread and is very effective.

To increase performance and endurance, some SSD manufacturers will reserve some of the drive capacity from the user area and dedicate it to the controller. This practice is known as over-provisioning (OP) and will increase the performance and longevity of the SSD. All current Kingston SSDs feature over-provisioning, and the capacities are 120GB, 240GB, 480GB, 960GB, 1.92TB and 3.84TB. Learn more about over-provisioning.

The NAND Flash used in USB, SD cards and SSDs all have endurance limits meaning one cannot continue to write to them forever. Flash based products will eventually wear out however with features like wear-levelling and over-provisioning an SSD will typically last longer than the system it was installed into. We measure drive endurance in TBW (Terabytes Written) and depending on drive capacity one can write hundreds of terabytes, up to petabytes. Performance of the SSD will remain the same throughout the life of the drive. Learn more about TBW.

S.M.A.R.T. stands for Self-Monitoring, Analysis, and Reporting Technology and is a part of the ATA standard. SMART attributes are used to measure drive “health” and enabled to warn the user (administrator, software program, etc.) of impending drive failure. Learn more about S.M.A.R.T.

Yes. Kingston SSDs can be used in USB, e-SATA, Thunderbolt and Firewire external enclosures. Note if the user chooses to enable a password via the ATA Security command, the drive will not be accessible via external enclosure.

HDDs are based on magnetic spinning platters, a technology that has been in use since the mid- 1950s. The data is written to and read from these spinning platters or disks via moving heads. HDDs are mechanical devices with many moving parts and are more prone to mechanical failures and failures due to environmental conditions such as heat, cold, shock and vibration.

Although the SSD market is growing and gaining more popularity, it is still relatively new. As with any new technology, it is only a matter of time before sales increase to a level that will allow manufacturing costs to reduce. In the last few years, the price gap between SSD and HDDs has gotten much smaller.

The only factor in favor of HDDs is the price per Gigabyte. HDDs are currently sold in capacities of 500GB and above, while SSDs are sold in capacities of 120GB and above. 

Traditional HDDs are best if mass storage is in the Terabytes is your primary need, while SSDs are excellent if performance is more important. It’s common to use an SSD as a boot drive to hold OS and applications and an HDD to hold data files.

Yes. Kingston offers SSD drives in upgrade kits that include all the necessary items required to replace a notebook or desktop HDD with a Kingston SSD, including software to easily transfer the OS and important data. Please note: Some Kingston SSD drives do not include cloning software. Nonetheless, there's a number of free cloning software applications available for download via Google search.    

No. SSDs never need to be defragmented. Defragmenting an SSD can reduce the life of an SSD. If your system is set up to defragment automatically, you should disable or turn off defragmentation when using an SSD. Some operating systems will defragment automatically, so this feature should be disabled for Kingston SSDs.

SSDs come in several form factors and protocols. The first SSDs were 2.5”, used the SATA connection and the AHCI protocol which were the standard adapted for hard drives to easily accommodate upgrades from HDD to SSD. Later, NVMe was developed as a native flash storage protocol that allowed for faster transfer speeds and are found on some of the latest high-end PCs and laptops. All NVMe SSDs are either M.2, U.2, or AIC PCIe. SATA 2.5” SSDs have been around for a while and are still found in many PCs. Learn more about the differences between NVMe and SATA.

NVMe is particularly designed for Enterprise Storage environments, enabling six times the bandwidth, a triple latency improvement and multi-core support. It supersedes the SATA protocol, originally for spinning disk hard drives. Learn more about choosing NVMe for data centers.

NVMe SSDs in client systems, such as desktops, laptops and workstations greatly improve overall storage performance. NVMe is leading the new standard of SSDs and Kingston’s NVMe SSDs are designed to provide a range of storage solutions that are a great choice for new PC builds, as well as storage upgrades for desktops and laptops. Learn more about NVMe SSDs for Client Systems.

What is M.2? What is NVMe? How are these related to SATA, AHCI and what is the speed difference? We break down each acronym in our infographic to help you better understand how and why the latest SSD technology is faster and better. Learn more about the differences between NVMe and SATA.

For certain embedded applications where space is limited, the M.2 specifications provide for different thicknesses of M.2 SSDs – 3 different Single-Sided versions (S1, S2, and S3) and 5 Dual-Sided versions (D1, D2, D3, D4, and D5). Some platforms may have specific requirements due to limited space below their M.2 connector.

Kingston M.2 SSDs conform to the Dual Sided M.2 specifications and will fit in the majority of system boards that accept Dual Sided M.2 SSDs; please consult with your sales representative if you require Single-Sided for specific embedded applications.

M.2 was developed by the PCI-SIG and SATA-IO standards organizations and is defined in the PCI-SIG M.2 and the SATA Rev. 3.2 specifications. It was originally called the Next Generation Form Factor (NGFF), and then formally renamed to M.2 in 2013. Many people still refer to M.2 as NGFF.

The M.2 small form factor applies to many add-in card types, such as Wi-Fi, Bluetooth, satellite navigation, Near Field Communication (NFC), digital radio, Wireless Gigabit Alliance (WiGig), Wireless WAN (WWAN), and Solid-State Drives (SSDs).

M.2 has a subset of specific form factors strictly for SSDs.

All M.2 SSDs flush-mount into M.2 sockets on system boards. The M.2 form factor introduces a path to higher performance via a smaller footprint and is the future path for SSD technological advancement.In addition, no power or data cables are needed making cable management unnecessary. Like mSATA SSDs, M.2 SSDs just plug into a socket and the physical installation is complete.

The M.2 form factor was created to provide multiple options for small form factor cards, including SSDs. SSDs previously relied on the mSATA for the smallest form factor, but mSATA was unable to be scaled up to 1TB capacities at a reasonable cost. The answer was the new M.2 specification that allows for different M.2 SSD card sizes and capacities. The M.2 specification allows system manufacturers to standardize on a common small form factor that can be extended to high capacities where it is needed.

No, they are different; M.2 supports both SATA and PCIe storage interface options, while mSATA is SATA only. Physically, they look different and cannot be plugged into the same system connectors. The picture below shows an M.2 SSD and an mSATA SSD (you can see the connector is different, as are their card sizes):

M.2 2280 (above) compared to mSATA. Note the Keys (or notches) that will prevent them from being inserted into incompatible sockets.

No, both SATA and PCIe M.2 SSDs will use the standard AHCI drivers built into the OS. However, you may need to enable the M.2 SSD in the system BIOS before being able to use it.

In certain cases, the M.2 SSD socket could share PCIe lanes or SATA ports with other devices on the motherboard. Please review your motherboard documentation for additional information as using both shared ports at the same time could disable one of the devices.

There are 2 reasons for the different lengths:

1. The different lengths enable different SSD drive capacities; the longer the drive, the more NAND Flash chips can be mounted on it, in addition to a controller and possibly a DRAM memory chip. The 2230 and 2242 lengths support 1-3 NAND Flash chips while the 2280 and 22110 support up to 8 NAND Flash chips, which can enable a 2TB SSD in the largest M.2 form factor.
2. Socket space in the system board can limit the M.2 size: Some notebooks can support an M.2 for caching purposes, but only have a small space that will accommodate only a 2242 M.2 SSD (2230 M.2 SSDs are smaller still but not needed in most cases where 2242 M.2 SSDs will fit).

For SSD-based M.2 modules, the most commonly occurring sizes are 22mm wide x30mm long, 22mm x 42mm, 22mm x 60mm, 22mm x 80mm and 22mm x 110mm. The cards will be called after their dimensions above: The first 2 digits define Width (all 22mm) and the remaining digits define Length from 30mm up to 110mm long. So, the M.2 SSDs are specified as 2230, 2242, 2260, 2280 and 22110

The picture below shows a 2.5-inch SSD and a 2242, 2260, and 2280 M.2 SSDs:

There are many notebooks and motherboards that support the M.2 SSD. Please consult system specifications and user manual to check for compatibility before purchasing an M.2 SSD.

No, M.2 SSDs were not designed to be hot-pluggable. Please install and remove M.2 SSDs when the system is powered off.

Different socket types are part of the M.2 Specification that calls for supporting specific device types within a given socket.

Socket 1 is designed for Wi-Fi, Bluetooth®, NFC and WI Gig

Socket 2 is designed for WWAN, SSD (caching), and GNSS

Socket 3 is designed for SSDs (both SATA and PCIe, up to x4 performance)

You should always read the motherboard / system manufacturer’s information to confirm which lengths are supported, but many motherboards will support 2260, 2280 and 22110. Many motherboards will provide multiple retaining-screw offset, allowing a user to secure either a 2242, 2260, 2280, or even up to 22100 M.2 SSD. The amount of space on the motherboard will limit the size of M.2 SSDs that can be secured into the socket and used.

The B+M keys on an M.2 SSD allow for cross-compatibility on various motherboards if the appropriate SSDs protocol is supported (SATA or PCIe). Some motherboard host connectors may be designed only to accommodate M-key SSDs, while others may only accommodate B-key SSD. The B+M keys SSD was designed to address this issue; however, plugging in a M.2 SSD into a socket will not guarantee it will work, as that will depend on having a shared protocol between the M.2 SSD and the motherboard.

The M.2 specification defines 12 keys or notches in the M.2 card and socket interface; many are reserved for future use:

Currently defined M.2 keys (only B and M apply to M.2 SSDs)
Source: All About M.2 SSDs, SNIA, June 2014.

Specifically, for M.2 SSDs, there are 3 commonly used keys:

1. B-key edge connector can support SATA and/or PCIe protocol depending on your device but can only support up to PCIe x2 performance (1000MB/s) on the PCIe bus.
2. M-key edge connector can support SATA and/or PCIe protocol depending on your device and can support up to PCIe x4 performance (2000MB/s) on the PCIe bus, provided that the host system also supports x4.
3. B+M-key edge connector can support SATA and/or PCIe protocol depending on your device but can only support up to x2 performance on the PCIe bus.

The different key types are often labeled on or near the edge connector (or gold fingers) of the M.2 SSD and also on the M.2 socket.

Note that B keyed M.2 SSDs have a different number of pins at the edge (6) vs. M keyed M.2 SSDs (5); this asymmetrical layout prevents users from reversing the M.2 SSDs and attempting to plug a B keyed M.2 SSD into an M keyed socket, and vice versa.

The PCIe M.2 SSD would only be able to operate at PCIe x2 (2-lane functionality) speeds within that motherboard. If you purchase a motherboard that supports PCIe x4 speeds, your x4-capable M.2 SSD should work as expected within that environment. In addition, there are PCIe limitations on system boards where the total number of PCIe lanes could be exceeded, limiting the PCIe M.2 x4 SSD to either have 2 lanes or even none.

If the host system doesn’t support the PCIe protocol, the PCIe M.2 SSD will most likely not be seen by the BIOS and therefore would be incompatible with the system.

Performance would likely be similar; it would also depend on the specific controller inside the host system that the SSDs were using as well as the internal layout and controller of each SSD. The SATA 3.0 specification supports up to 600MB/s whether in a 2.5” or mSATA SSD form factors.

No. An M.2 SSD will support either SATA or PCIe, but not both at the same time. In addition, system board sockets will be designated by manufacturers to support either SATA, PCIe, or in some cases, both. It is important to check your system’s manual to verify which technologies are supported.

The PCIe interface is faster, as the SATA 3.0 spec is limited to ~600MB/s maximum speed, while PCIe Gen 2 x2 lanes is capable of up to 1000MB/s, Gen 2 x4 lanes is capable of up to 2000MB/s, and Gen 3 x4 lanes of up to 4000MB/s.

Kingston’s solid-state drives are built using NAND Flash Memory.

Kingston SSDs are OS independent and will run on any system supporting a standard SATA interface.

Kingston SSD drives are plug-and-play, and no additional drivers are required.

Most systems can be upgraded with Kingston SSDs. Legacy systems going back to SATA II can be upgraded with Kingston SATA SSDs. Modern systems support SATA III, PCIe NVMe, or both. These systems can be upgraded with Kingston SATA SSDs and high-performance Kingston PCIe NVMe SSDs. To select the correct Kingston SSD for your system you can use the Kingston configurator or contact Kingston Technical Support for assistance.

It is highly recommended to use Kingston Data Center (DC) series SSDs for RAID configurations. Kingston Data Center series SSDs offer better RAID controller compatibility, are specifically tuned for demanding data center/enterprise workloads, and offer higher performance and endurance than client SSDs.

It is very common that SAS (Serial Attached SCSI) based systems and controllers also support SATA devices. Kingston recommends that users check with the system or controller documentation to make sure that both SATA and SAS drives are compatible. If they are, Kingston SSDs may be successfully used.

All Kingston SSDs use an intelligent and efficient garbage collection process that improves drive life with little impact on Flash endurance and is invisible to the user. Learn more about SSD garbage collection.

Kingston SSDs integrate advanced wear-levelling techniques that incorporate a block picking algorithm capable of extending flash endurance and optimizing drive life. This unique wear-levelling ensures that the individual Flash memory blocks are consumed at a very balanced rate, not to exceed a 2% difference between the most often written blocks and least written.

Trim and garbage collection are technologies that modern SSDs incorporate to improve both their performance and endurance. When your SSD is in its fresh out of box condition all of the NAND blocks are empty so the SSD can write new data to the empty blocks in a single operation. Over time most of the empty blocks will become used blocks that contain user data. In order to write new data to used blocks the SSD is forced to perform a read-modify-write cycle. The read-modify-write cycle hurts the SSDs overall performance because it now must do three operations instead of a single operation. The read-modify-write cycle also causes write amplification which hurts the SSDs overall endurance.

Trim and garbage collection can work together to improve SSD performance and endurance by freeing up used blocks. Garbage collection is a function built into the SSD controller that consolidates data stored in used blocks in order to free up more empty blocks. This process happens in the background and is completely handled by the SSD itself. However the SSD may not know which blocks contain user data and which blocks contain stale data that the user has already deleted. This is where the trim function comes in. Trim allows the operating system to inform the SSD that data has been deleted so that the SSD can free up those previously used blocks. For trim to work both the operating system and the SSD must support it. Currently most modern operating systems and SSDs support trim however most RAID configurations do not support it.

Kingston SSDs take advantage of both garbage collection and trim technologies in order to maintain the highest possible performance and endurance over their lifetime.

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