Explaining SSDs: Form Factors, Interfaces & Technologies

Summary

This video from Explaining Computers covers the various form factors, interfaces, and technologies of solid-state drives (SSDs). It explains the differences between two-and-a-half-inch and M.2 SSDs, the importance of selecting the right interface (SATA vs. PCIe/NVMe), and the implications of different memory cell technologies (SLC, MLC, TLC, QLC, PLC) on performance and lifespan. The video also highlights the significance of choosing compatible SSDs for specific systems, the labeling conventions of manufacturers like Samsung, and the impact of SSDs on modern computing efficiency.

Takeaways

• 💾 SSDs are replacing traditional hard drives in many computers due to their speed, power efficiency, and robustness.
• 📏 SSDs come in various form factors, with 2.5-inch and M.2 being the most common, each with different dimensions and installation methods.
• 🔢 M.2 SSDs are identified by a code that specifies their width and length, such as 2280 for 22mm width and 80mm length.
• 💻 Some high-end SSDs, like the Nimbus Extra Drive DC 100, offer massive storage capacities but come with a premium price tag.
• 🔌 There are different SSD interfaces, including SATA with a max speed of 550 MB/s and PCIe NVMe with speeds up to 7000 MB/s.
• ⚠️ The form factor of an SSD does not determine its interface; M.2 SSDs can have either SATA or NVMe interfaces.
• 🛠️ When purchasing an SSD, it's crucial to ensure compatibility with the system's motherboard and supported interfaces.
• 🔑 M.2 SSDs have different keys (B-key, M-key) to prevent incorrect installation into the wrong slot on the motherboard.
• 🔬 SSDs use NAND flash memory with technologies like floating gate and charge trap flash to store data.
• 🔄 SSDs have a limited number of program/erase (P/E) cycles, which affects their lifespan and reliability.
• 📈 SSDs have evolved from SLC (single level cell) to MLC, TLC, QLC, and potentially PLC, with each generation storing more bits per cell but having fewer P/E cycles.

Q & A

What are solid-state drives (SSDs) and how do they differ from traditional hard drives?

Solid-state drives (SSDs) store data on solid-state flash memory chips, making them faster, more power-efficient, and more robust than traditional hard drives, which use spinning disks to read and write data. SSDs are also more expensive per gigabyte compared to hard drives.

What are the common form factors of SSDs?

The most common SSD form factors are 2.5-inch and M.2. 2.5-inch SSDs are the same size as 2.5-inch hard drives, while M.2 SSDs are smaller and can vary in size, with dimensions expressed in a code like 2280, indicating 22mm width and 80mm length.

How do 2.5-inch SSDs connect to a computer?

2.5-inch SSDs connect to a computer using a cable that plugs into a connector on the end of the drive, and then the drive is mounted with screws.

What is the significance of the 2280 M.2 SSD size code?

The 2280 size code for an M.2 SSD indicates that the SSD is 22 millimeters wide and 80 millimeters in length.

What is the difference between SATA and PCIe interfaces for SSDs?

SATA (Serial Advanced Technology Attachment) has a maximum data transfer speed of around 550 megabytes per second, while PCIe (Peripheral Component Interconnect Express) with NVMe (Non-Volatile Memory Express) can reach speeds up to 7000 megabytes per second for the latest drives connected via PCIe 4.0 interface.

Why is it important to match the SSD form factor with the motherboard?

It is important to match the SSD form factor with the motherboard to ensure the SSD fits and works properly. M.2 SSDs, for example, can come in various sizes and not all motherboard slots can accommodate all M.2 sizes.

What is the difference between SATA and NVMe interfaces in terms of data transfer speeds?

SATA interfaces have a maximum data transfer speed of about 550 MB/s, whereas NVMe interfaces can support speeds up to 7000 MB/s with the latest PCIe 4.0 interface, making NVMe significantly faster.

What is the role of the NAND logic gate in SSDs?

NAND logic gates in SSDs are used to store data in flash memory cells. By applying voltage, electrons are moved into a floating gate or charge trap layer, changing the resistance that can be measured to read data. To erase data, a voltage or field is applied to remove the electrons.

What are the different levels of data storage in SSD memory cells, and how do they affect performance and lifespan?

SSDs can use Single-Level Cell (SLC), Multi-Level Cell (MLC), Triple-Level Cell (TLC), and Quad-Level Cell (QLC) technologies, with each level storing more bits per cell. Higher levels of data per cell increase capacity and reduce cost but decrease the number of program/erase cycles the SSD can sustain, affecting speed and lifespan.

How does Samsung label its SSDs in terms of data bits stored per memory cell?

Samsung labels its SSDs as 'MLC' regardless of the number of bits stored per cell. For example, a Samsung Pro drive is labeled as 2-bit MLC, while a Samsung CUVO drive, which is actually QLC, is labeled as 4-bit MLC.

What are the advantages of using SSDs over traditional hard drives in computing devices?

SSDs offer advantages such as faster boot times, improved overall performance, increased robustness due to no moving parts, and better battery life in portable devices like laptops.

Outlines

00:00

💾 SSD Form Factors and Interfaces

This paragraph introduces the concept of solid-state drives (SSDs) and their evolution from traditional hard drives. It discusses the various form factors of SSDs, such as the 2.5-inch and M.2 sizes, and their connection methods to the computer. The M.2 SSDs are highlighted with their size codes like 2280, explaining the dimensions in millimeters. It also touches on less common form factors like the 3.5-inch Nimbus Extra Drive DC 100 and AIC (Add-in Card) SSDs. The paragraph emphasizes the importance of choosing the correct SSD form factor and interface, such as SATA and PCIe/NVMe, for compatibility with the user's system.

05:00

🔌 Understanding SSD Interfaces and Compatibility

The second paragraph delves into the distinction between SSD form factors and interfaces, clarifying that an SSD's performance is not solely determined by its physical size. It dispels the myth that M.2 SSDs are inherently faster than 2.5-inch SSDs, as both can have either SATA or NVMe interfaces. The paragraph explains the importance of matching the SSD interface with the system's motherboard, especially when dealing with M.2 SSDs that can be either SATA or NVMe. It also mentions the U.2 and SAS interfaces found in some enterprise-grade SSDs and the confusion that can arise from different M.2 SSD lengths not indicating interface differences. The paragraph concludes with a table summarizing the interfaces available for various SSD form factors.

10:00

🛠 SSD NAND Technologies and Their Implications

This paragraph focuses on the technologies used in SSDs to store data, specifically NAND logic gates. It explains the process of writing, reading, and erasing data using floating gate or charge trap flash technologies. The paragraph discusses the impact of repeated program/erase (P/E) cycles on the longevity of SSDs, leading to the introduction of different types of NAND: Single Level Cell (SLC), Multi-Level Cell (MLC), Triple Level Cell (TLC), and Quad Level Cell (QLC). It also mentions the upcoming Pentalevel Cell (PLC) technology. The summary highlights how the number of bits stored per memory cell affects the drive's speed, capacity, and life expectancy. The paragraph concludes with a note on Samsung's unique labeling of their drives, which can cause some confusion due to their use of 'MLC' to denote the total number of bits stored per cell.

Keywords

💡Solid-State Drives (SSDs)

SSDs are data storage devices that use solid-state flash memory to store data, as opposed to traditional hard drives that use spinning disks. They are faster, more power-efficient, and more robust than hard drives. In the video, SSDs are the main focus, with various form factors, interfaces, and technologies being discussed, illustrating their importance in modern computing for improved performance and reliability.

💡Form Factors

Form factors refer to the physical size and shape of a device, such as an SSD. The video mentions 2.5-inch and M.2 as common SSD form factors, with M.2 drives having various sizes denoted by a code (e.g., 2280, 2260). Understanding form factors is crucial for compatibility with different computer systems.

💡Interfaces

Interfaces in the context of SSDs are the methods by which the drives connect to the computer's motherboard. The video discusses SATA and PCIe NVMe as the two most common interfaces, with SATA offering speeds up to 550 MB/s and PCIe NVMe capable of up to 7000 MB/s. The interface determines the data transfer speed and thus the performance of the SSD.

💡M.2 SSDs

M.2 SSDs are a type of SSD that is designed to directly connect to the motherboard using the M.2 slot. They come in various sizes and can have either a SATA or NVMe interface. The video emphasizes the importance of ensuring the correct interface type when purchasing an M.2 SSD for a specific system.

💡SATA

SATA stands for Serial Advanced Technology Attachment and is an interface used for connecting storage devices, including SSDs, to a computer. The video explains that SATA SSDs have a maximum data transfer speed of around 550 MB/s, making them a common choice for consumer drives.

💡PCIe NVMe

PCIe NVMe, or Peripheral Component Interconnect Express Non-Volatile Memory Express, is an interface that allows SSDs to connect via PCIe slots on the motherboard. The video mentions that NVMe SSDs can achieve much higher data transfer speeds compared to SATA, making them suitable for high-performance applications.

💡Program/Erase (P/E) Cycles

P/E cycles refer to the number of times data can be written to and erased from an SSD's memory cells. The video explains that this number is finite and varies depending on the type of memory cell technology used, which affects the SSD's lifespan and reliability.

💡NAND Flash

NAND flash is the type of memory used in SSDs to store data. The video describes two technologies used in NAND flash: floating gate and charge trap flash. These technologies determine how data is written, read, and erased in SSDs.

💡Single Level Cell (SLC)

SLC is a type of NAND flash memory where each cell stores one bit of data, requiring only two possible states. The video explains that SLC drives can sustain a high number of P/E cycles, making them more reliable but also more expensive.

💡Multi-Level Cell (MLC)

MLC, or Multi-Level Cell, is a NAND flash technology where each cell stores two bits of data, requiring four possible states. The video mentions that MLC drives are more common and cost-effective than SLC drives but have a lower P/E cycle count and potentially slower performance.

💡TLC and QLC

TLC (Triple Level Cell) and QLC (Quad Level Cell) are NAND flash technologies where each cell stores three and four bits of data, respectively. The video explains that these technologies allow for higher storage capacities at a lower cost but come with trade-offs in speed and endurance.

Highlights

SSDs have replaced traditional hard drives in many computers due to their faster, more power-efficient, and more robust nature.

SSDs are more expensive per gigabyte compared to hard drives but offer superior performance.

SSDs come in various form factors, with 2.5-inch and M.2 being the most common.

2.5-inch SSDs are the same size as traditional hard drives and use a similar cable connection.

M.2 SSDs are mounted directly onto the motherboard and come in various sizes denoted by a code.

M.2 SSDs can have different lengths, but this does not affect their interface type.

There are high-capacity SSDs like the Nimbus Extra Drive DC 100, which is a very expensive enterprise device.

AIC (Add-In Card) SSDs connect directly to a PCIe slot and come in different sizes.

MSATA is an older SSD form factor still found in many laptops and mobile devices.

SSDs can have SATA or PCIe interfaces, with PCIe offering much higher data transfer speeds.

The form factor of an SSD does not determine its interface; M.2 SSDs can be either SATA or NVMe.

It's crucial to ensure the SSD's interface matches the system to avoid compatibility issues.

SSDs use NAND logic gates with floating gate or charge trap flash technologies for data storage.

SSDs have a limited number of program/erase cycles before they fail, affecting their lifespan.

Different SSD technologies store varying bits per memory cell, affecting speed and life expectancy.

Samsung labels its drives with a bit count system, which can cause confusion with traditional MLC, TLC, and QLC labels.

SSDs have significantly improved laptop portability, robustness, and battery life, as well as computer boot times and overall performance.

Transcripts

[Music]

welcome to another video from explaining

computers

this time i'm going to talk about these

things solid-state drives

or ssds specifically i'm going to

explain all of the different ssd form

factors

interfaces and technologies so

let's go and get started

for many years almost all computers

stored their operating systems

programs and data on hard drives with

three and a half inch models being most

common in desktop pcs

whilst two and a half inch drives were

found in most laptops

however today an increasing proportion

of computers use an ssd

instead of or addition to a hard drive

ssds stored data on solid-state flash

memory chips

which makes them faster more power

efficient and more robust

this said the cost of storing data on an

ssd is still greater per gigabyte

than using a hard drive

today ssds come in many different sizes

or form

factors with the most common being two

and a half inch and

m.2 as we can see two and a half inch

ssds

are the same size as two and a half inch

hard drives and they connect to a

computer using a cable which plugs into

a connector on the end of the drive

and then the drive then mounts with

screws

meanwhile m.2 drives usually stock

directly into a computer's motherboard

and come in a variety of sizes which are

expressed as a code

for example this is a 2280 m.2 ssd

which means this is 22 millimeters wide

and 80 millimeters

in length and this is a 2260 m.2 ssd

which is therefore 22 millimeters wide

and 60 millimeters long

other possible dimensions for m.2

devices are 1630

2230 3030 2242

3042 and 2210

although not all of these are used for

m.2 ssds

when purchasing an m.2 ssd it is of

course critical to get one which will

fit your motherboard

although it's worth noting that many

motherboard slots can accommodate

several

m.2 sizes

while two and a half inch m.2 ssds are

the most common other form factors

are available not least there are a few

three and a half inch ssds

such as the nimbus extra drive dc 100

with a 100 terabyte capacity this is

currently the highest capacity ssd

on the market and is a very high-end

enterprise device

with a forty thousand dollar price tag

to match

also at the higher end of the market we

find aic

or add-in card ssds that plug directly

into a pcie slot on a computer's

motherboard

these also come in different sizes and

most usually

hhh l which stands for half height half

length

or fhhl which stands for full height

half

length examples include the samsung

pm1733

and the wd black an1500

note that there are also pcie add-in

card adapters that allow

one or more m.2 ssds to be plugged into

a standard

pcie slot

a final fairly common if older ssd form

factor

is msata this was defined in 2011

before m.2 was specified in 2013

and can still be found in many laptops

and other mobile devices

however this all said today if you are

purchasing a new ssd

it is most likely you'll be selecting a

two and a half inch form factor drive

or an m.2 drive

ssds are available with a variety of

different interfaces

with the two most common being sata and

pcie

mvme sata stands for serial advanced

technology attachment

and delivers a maximum data transfer

speed of around 550 megabytes a second

meanwhile pcie stands for peripheral

component interconnect

express with nvme or non-volatile memory

express

being a standard for connecting ssds via

pcie

you may see ssds labeled as having a

pcie interface

an nvme interface or a pcie nvme

interface but today all of these refer

to the same thing

maximum data transfer speeds for nvme

ssds or up to 7000 megabytes a second

for the latest drives connected to

computers with a pcie

4.0 interface

now it is very important to appreciate

that an ssd's form factor

does not determine its interface

very frequently i read comments here on

youtube that say things like

m.2 ssds are better than two and a half

inch ssds because m.2 drives are

faster and this is not always true

for start m.2 ssds can have either a

sata

or an nvme interface so for example here

this western digital m.2 drive

is an nvme drive but this transcend

drive is

a sata drive and so operates at the same

speed as most

two and a half inch drives which have a

satter interface

this said there are two and a half inch

drives that have a pcie

nvme interface known in this context as

u.2

the connectors on sata and udot two two

and a half inch ssds

do look fairly similar but they are not

identical

as this graphic shows examples of two

and a half inch ssds with the u.2 pcie

nvme interface include the kingston

dc1000m

and the wd gold enterprise class nvme

ssd it's also worth noting that some two

and a half inch enterprise ssds

come with a serial attached scussy or

sas interface

that can provide data transfer speeds of

up to 1200 megabytes a second

or twice that of saturn

now because ssds with the same form

factor can have different

interfaces it becomes very important to

purchase the right drive for your system

if you want it to fit and work properly

when purchasing a two and a half inch

ssd you should have no problems in

practice

as all consumer drives have a saturn

interface with u.2 and sas connectors

being rare on most motherboards you're

therefore very unlikely to purchase a

u.2 or sas two and a half inch ssd

by accident the same however

is unfortunately not the case when it

comes to m.2 drives with

many reported instances of people

purchasing an nvme m.2 ssd where it

needs a nasa one

and vice versa so it's incredibly

important to check just which kind of

m.2 ssd

your system supports today most new

motherboards have slots that work with

both sata

and nvme m.2 drives but there is still a

lot of older desktop motherboards and

laptops out

there but are sata or nvme only

nvme and sata m.2 drives do look

identical

and i'd note that the different lengths

of these drives has nothing to do with

their different

interface it's also important to note

that all m.2 devices have slots or

keys to prevent them being fitted into

the wrong kind of m.2 slot

specifically m.2 ssds can be either b

keys

m keys or both here like all modern nvme

drives

this wd black is m keyed whilst

like most sata drives this transcend is

both b

and m keyed finally

just to make sure everything is as clear

as possible let's finish this segment

with a table

indicating the different interfaces

available in different ssd

form factors as we can see 2.5 inch ssds

can have a sata u.2 nvme or sas

interface

while m.2 drives can be sata or mvm

e meanwhile pcie add-in card ssds are

only ever pcie

mvme whilst msata or mini satur ssds are

only ever satter

as their name suggests

most ssds store data in their flash

memory chips

using nand logic gates two technologies

are commonly used

called floating gate and charge trap

flash

in both of these to write or program

data

a voltage is applied to move electrons

into a floating gate

or charge trap layer the presence of

these electrons

changes the resistance between the

membrane cell's source and drain

electrodes

and this can be measured by passing a

current between them so allowing data to

be read from the cell

to erase the cell a voltage or field is

applied to remove the electrons from a

floating gate or

charge trap layer however repeated

program arrays operations

weaken the material the cell is made

from which results in electrons either

escaping a floating gate

or being retained in the charge trap

layer

after a certain number of program arrays

or pe cycles

it therefore becomes impossible for the

cell to reliably function

the practical implication is that all

ssds can only sustain a limited number

of data right operations

before they fail

the technology in the first ssds was

called single level cell

or slc and stored just one bit of data

per memory cell

the cell was therefore only required to

maintain two possible states

of fully programmed or fully erased

however today

most ssds store multiple bits of data

per memory cell

in order to increase drive capacity at a

reduced cost

inevitably this reduces the number of

program arrays cycles and ssd can

reliably sustain

and also makes the drive operate more

slowly

therefore when you purchase an ssd you

may wish to consider how many bits of

data it stores per memory sell

as this will determine its speed and

life expectancy

after slc ssds came multi-level cell or

mlc drives that store two bits of data

per memory cell

so requiring the cell to reliably

distinguish four programmed states

next came triple level cell or tlc ssds

followed by quad level cell or qlc

today manufacturers including intel and

toshiba

are working on pentalevel cell or

plc-ssds

although these are yet to arrive on the

market

the programmer raised life expectancy

for any individual ssd

varies significantly but as a guide

slc drives can sustain up to about one

hundred thousand programmer race cycles

mlc about 3 000 for consumer drives

tlc somewhere between 500 and 2000

and qlc between 300 and 1000

whilst these numbers may seem very low

it should be remembered that most users

only write or rewrite data to a very

small percentage of their drive

on a daily basis and so even qlc and

future plc drives

will work reliably for many years for

the vast majority

of the users

having just explained slc mlc

tlc qlc and plc

i thought it was important to finish off

by saying a few words about how

samsung chooses to label its drives and

its technical specs because

it can make matters slightly confusing

and this is because samsung labels

every drive it has as being mlc and that

indicates the total number of bits

stored

the cell so for example here is a

samsung pro drive which is

mlc which samsung labels as 2-bit

mlc that's not too confusing but over

here

we have a samsung cuvo drive which is

qlc

but samsung labels this as four bit mlc

four bit multi-level cell which i

suppose is technically correct if you

just use multi-level cell to mean

multi any number when you define a

number of bits stored

alongside it but in the world where

we've generally taken mlc to mean two

bits per cell that can

confuse matters a bit so here's a little

table just to explain what samsung

does with mlc being two 2-bit mlc

tlc being 3-bit mlc qlc being 4-bit mlc

and presumably in time plc will be

labeled on samsung drives as

5-bit mlc

over the past decade ssds have helped to

make laptops lighter

more robust and to have an improved

battery life

as well as allowing computers of all

kinds to boot more quickly

and to benefit more generally from

faster storage technology

if you want to know more about different

types of computer hardware you may want

to check out some of the other videos

on this channel including explaining ram

and explaining pcie slots

but now that's it for another video if

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