Explaining SSDs: Form Factors, Interfaces & Technologies
Summary
TLDRThis 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
💾 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.
🔌 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.
🛠 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.
Mindmap
Keywords
💡Solid-State Drives (SSDs)
💡Form Factors
💡Interfaces
💡M.2 SSDs
💡SATA
💡PCIe NVMe
💡Program/Erase (P/E) Cycles
💡NAND Flash
💡Single Level Cell (SLC)
💡Multi-Level Cell (MLC)
💡TLC and QLC
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
you've enjoyed what you've seen here
please press that like button
if you haven't subscribed please
subscribe and i hope to talk to you
again
very soon
you
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