If you've ever installed an application or an operating
system, you'll notice there's a specification that
requires you have a certain amount of memory
inside of your system.
This memory is referring to random access memory or RAM.
It's the type of memory we commonly use inside
of our personal computers.
This is very specifically talking about the memory
modules or sticks of memory that are inside of your computer.
This is not referring to an SSD or a hard drive storage space.
This is specifically referring to the high speed
temporary storage area that's commonly
used when you load an application or document.
You're only able to use these applications and documents when
all of that information is loaded into memory.
If you go back in time and look at much older videos for A+,
you'll notice there are a number of different memory slots that
were mentioned.
But these days, practically everyone
uses exactly the same type of memory slots
in their computers.
These are designed to transfer data very quickly
between the information that's in the memory modules
and the CPU of your system.
The faster you can transfer information between those two
components, the faster your overall system will be.
However, the specific type of memory in your system
can vary widely so make sure you look
at your motherboard documentation
to know exactly what type of memory
needs to be installed in those memory slots.
What fits into those memory slots
is a dual in-line memory module or what we commonly
refer to as a DIMM.
This is a dual in-line memory module
because the connectors that are on one side of the memory
module are different than the connectors that
are on the other side of the memory module.
Another common specification for these DIMMs
is information is transferred in and out of the DIMM
in 64-bit data widths.
So we're able to transfer these blocks of information
to the CPU or the storage devices that are on our system.
Here's the installation of a DIMM
onto these memory slots on a motherboard.
To install the memory, you would push
it very lightly into that slot, and there
are clips on the end that will hold that memory in place so
that it can't accidentally be removed.
If you're using a laptop, then you're
probably not using the full sized DIMM.
Instead, you're using a SO-DIMM.
The SO stands for small outline dual in-line memory module,
and it's about half the width of a normal dual in-line memory
module.
These are very common on laptops and other mobile devices,
where space is at a premium because these modules are
so much smaller than the full sized DIMMs.
Here's a view of the installation of a SO-DIMM.
You can see that these are a lot smaller than the full size
DIMMs, and they, just like the other DIMMs,
will fit into a slot and then push down and lock in place.
Here's a picture of a DIMM and a SO-DIMM next to each other.
This is to scale.
So this is exactly the sizes that you would see,
and you can see that a SO-DIMM really
is about half the width of a standard size DIMM.
On the memory module itself, you'll
notice that there are these black components.
That is the random access memory or RAM that
is located on those modules.
This is the memory itself, and we often
refer to this as dynamic random access memory or D-RAM
because this constantly needs to be
refreshed so that the data does not disappear.
This is one of the requirements for this type of memory
is that there's always a power source providing
that refreshing of the information that's
in these memory modules.
And the random part of the random access memory
means that we can access any data that's
on any part of this module by simply asking for it.
We don't have to fast forward or rewind through this module.
We can simply request a particular area of memory
and have that information provided
to us directly from the dynamic random access memory.
On our personal computers, this memory
is not only dynamic and random, it is also synchronous.
There's a clock on our system that regulates the flow of data
in and out of these memory modules, and every clock cycle,
there will be some data that is transferred either
in or out of this system.
This provides a standard time frame
for sending or receiving data from your memory.
This also allows all the other components
of your motherboard to know exactly when this data will
be transferred.
You may have noticed in these images of the DIMMs
or the SO-DIMMs that there are notches on the bottom
of the module, and depending on the type of memory
you're using, the notches may be in a different place.
These notches prevent us from using the wrong type of memory
in our system.
So if you try to install a DDR2 module
into a system with a DDR3 slot, you'll
notice that particular notch will not allow that memory
to be installed.
As I mentioned earlier, there's a clock inside of our computer
that keeps track like a metronome,
so we know exactly when data will be transferred
in and out of memory.
If you're using a much older computer that has single data
rate memory, then one clock cycle
is able to transfer one bit of data.
So you can see what the single clock cycle,
we have data one, data two, data three and so on.
Our modern systems use double data rate memory or DDR.
This double data rate can transfer twice
in a single clock cycle, which means
we can effectively transfer twice as much
than a single data rate.
As our systems have evolved through the years,
we've also updated our memory modules.
Version 3 of this memory type is double data rate three or DDR3.
These were an improvement over the older DDR2 memory
and allowed you to increase the data
rates to be twice as fast as those older DDR2 systems.
We're also able to have memory modules that
have a maximum amount of RAM of 16 gigabytes per module.
And remember, there's no backwards
compatibility with these memory modules,
so this notch at the bottom ensures
that this will only be installed on a system that
can support DDR3.
On newer systems, you may find DDR4,
which increases the speed over DDR3, but perhaps
even more importantly, increases the maximum amount of storage
on a single module to 64 gigabytes.
Again, this is not backwards compatible
with previous versions, so if you want to use DDR4 memory,
you'll need a motherboard that can support this memory type.
And you may find some systems that can support faster memory
in the form of DDR5.
This still has a maximum total size
per module of 64 gigabytes, but it is a faster throughput
than the older DDR4.
And of course, this notch or key that's on the memory
has moved so you can only use DDR5 memory on a motherboard
specifically designed for DDR5.