Instructor: In this lesson,
we're going to take a look at expansion cards.
Now expansion cards come in five different types,
but only two are really seen in modern computers.
We're going to cover all five for the sake of completeness.
But really, you want to focus on two main types,
PCIe known as PCI Express, and Mini PCIe
or Mini PCI Express,
which is used in laptops and small form factor devices.
First, we have PCI, and this is really where it all began.
PCI was the first 32-bit expansion card.
Now PCI was originally developed back in the early 1990s
to provide expansion slots for things like network cards
and video cards and audio cards and modems,
and storage host controllers and things like that.
Before PCI, there was an older technology
that worked on 8-bit and 16-bit computers called ISA.
But we really don't even need to get into that
because you're not going to see any of those in the real world.
You will still see some older PCI cards,
which are these older 32-bit cards
that we're talking about right now.
Now, when you're dealing with PCI,
it is actually going to be a faster
and more robust expansion card slot than ISA was,
but it's still an older technology
and relatively slow in modern networks.
For example, if you're looking at a standard PCI card,
which is a 32-bit interface,
it only supports a maximum bus speed of about 33 megahertz.
This means we can get a maximum data transfer rate
of only 133 megabytes per second.
Now this is calculated by taking that 32-bit bus,
which tells you how many bits can be pushed across
the bus at a given time.
If we divide 32 by eight, that takes 32-bits
divided by eight to give us four bytes.
Now four bytes is not a lot of data.
And because we only have a 33 megahertz bus speed,
this means we have 33,000,000 hertz or 33,000,000 cycles per second.
So in each second, I can send 33,000,000
times four bytes across the wire.
That means when we calculate that
we only get 133 bytes per second,
which is how we get to 133 megabytes per second.
As you can see, it's not a lot of data.
Most modern networks, for instance,
can do one gigabit per second or more.
And most data connections
can do six gigabytes per second or more.
So these PCI cards just really can't push that much data,
and therefore they had to be replaced.
As we move to 64-bit operating systems,
going from an x86 architecture
to an x64-based architecture,
there was a newer card that came out called PCI-X.
Now PCI-X is written as PCI-X in all capital letters.
And this again is an older card
that you're not really going to find that much these days.
Now, this newer card was a 64-bit card,
so it had doubled the amount of information
every second being sent.
But in addition to that,
it actually moved from a 33 megahertz bus
to 133 megahertz bus
giving us a really large incremental speed increase.
Now there's also another version
is called PCI-X version two.
And that actually went up to a 266 megahertz bus
or even up to a 533 megahertz bus.
And this means we can actually push a lot of data
and so it was relatively fast.
Now the big problem was when they developed PCI-X,
they made it fully backwards compatible.
So if you had a motherboard that supported two PCI cards
and two PCI-X cards,
and you mixed and match them,
what would end up happening is all of the bus
had to slow down for the slower speeds.
So taking 533 megahertz for that PCI-X bus,
you now had to downgrade and go down to 33 megahertz
to support the older PCI bus as well.
Now, in addition to this, most PCI and PCI-X
was used for things like networking cards
and audio cards and things like that.
But it wasn't great for graphics,
because it really wasn't fast enough for that.
So back in the day, they created something known as AGP.
Now AGP stands for the advanced graphics port.
Now this is because PCI was simply too slow
for the newer 3D games that were coming out
in the late '90s and early 2000s.
So they created this thing called AGP,
which was a dedicated port that could only be used
for video graphics cards.
Now AGP came in multiple flavors,
including a 1x 2x 4x and 8x slot.
Now depending on which slot you used,
it had different amounts of power required
and it was able to give you faster speeds.
Now AGP was quite popular in the late '90s and early 2000s.
But these days, it's very rare to find AGP
in any modern computers,
because they were replaced
by what is known as PCIe or PCI Express.
And that's really what we need to focus on here.
Now PCI Express was really good
because it allowed us to replace PCI, PCI-X and AGP.
In fact, in most motherboards,
you're only going to find PCIe slots
in the modern motherboards.
Now these PCIe slots come in
a variety of different sizes though.
These are known as x1, x4, x8, and x16.
Normally, we will write this as PCI, all capital,
and then a little e to signify Express
and then a space, x and the number.
So if you're using a shorter one,
this is known as a PCIe x1.
If you're using a graphics card,
this tends to be put into a PCIe x16.
Now the reason it's called x something
is because this is how long the bus is.
And this tells you how much data can be pushed
at a given time.
If you're using a PCI x1 card,
this is a very small and short connector to the motherboard
and it can only send a small amount of data relative
to an x16 slot.
Because of this, we tend to see x1 and x16
being the most commonly used on motherboards
with x1 being used for things like modems,
network cards, wireless cards, input output devices,
audio cards, and things like that.
On the other hand, usually what you're going to see used
for a PCIe x16 card is going to be a graphics card.
And this is because they support a large amount of data
and very fast speeds.
When you're dealing with a PCIe card,
which is known as a peripheral component
interconnect express interface.
This will connect to the bus
and it is the fastest way to get data
to and from the motherboard
for any external devices or additional expansion cards.
This uses a point-to-point serial connection.
And this means that each component
that's plugged into the slot
is going to have direct access to the motherboard
without having to share that bus with anybody else.
Compare this is something like USB,
where you have multiple devices
that can be chained together to a single USB port
and they have to share all that bandwidth.
Now the reason this is called a PCIe x something
is because we're talking about
how many lanes of traffic
are being dedicated to those devices.
Now the total number of lanes that are supported
by this PCI Express bus
is going to be determined by your motherboard
and its form factor.
This might support something like 16 or 24 or 32.
So if you have a motherboard that supports 24 lanes,
even though you have two x16 slots,
if you had 16 and 16, that's 32.
If you use both of them, it's actually going to slow down,
because you only have 24 available lanes.
Think about it like the highway near your house.
If there's five lanes on the highway,
and there's five cars sitting side by side,
they can all go as fast as they want
because they have individual lanes.
But if I put six cars in those five lanes,
now somebody's going to have to slow down behind somebody else,
because they all can't go side by side through that path.
And that's the idea when you start dealing
with PCIe or PCI Express.
It's all about the number of lanes that are available.
For this reason, it's really rare to see
x4 or x8 connections anymore.
Most of the time, you're going to see things like x16 and x1
because it maximizes the amount of lanes
that can be used on that particular motherboard.
Because most motherboards support
this type of a configuration better
and most cards are either built as an x1
for low speed devices like input/output devices,
and then having a high speed reserve for video
when you're using those x16 slots.
Now when you look at PCIe,
there's also multiple versions of it.
Going from one, two, three, four, and five.
As you increase in the version,
you also increase in the speed of transfer.
Now for the exam, you don't need to memorize
the different transfer rates for PCIe.
What you should remember is that PCIe x1
is going to be slower than PCIe x16.
PCI e x16 is going to be used
for things like video graphics cards,
especially in gaming computers.
Whereas when you're using an x1 slot,
it's usually going to be used for things like networking cards,
storage cards, or other input/output type of devices.
When you're looking at different versions of PCIe,
remember, the higher the number, the faster the speed.
And this makes sense, because in most technology,
newer versions are going to be faster
and better than the older technology or older versions.
When you connect an expansion card to the PCIe slot,
it's going to be able to draw its power through that slot.
By default, all the PCIe Express slots
will provide 25 watts of power.
Now on some motherboards,
there'll be a dedicated graphics adapter slot
for a PCIe x16.
And it may be colored differently or looked differently
or notated differently on the motherboard.
This specialized graphics card slot
actually can provide up to 75 watts of power
instead of 25 watts of power,
because it is that dedicated graphics card slot.
So keep that in mind as well.
The final thing to realize
when it comes to PCIe or PCI Express
is that because the slots are different sizes,
you can visually look at them and know what it is.
An x1 slot is smaller than an x4, or an x8, or an x16 slot.
And each one is going to be basically
double the size of the one before it.
So if you take an x1 slot and you double the size,
you get to an x4.
If you double an x4, you get to an x8.
If you double an x8, you get to an x16.
Now if you have a device that is smaller,
you can still go into a larger card.
For example, on my motherboard I have four slots,
two x1s and two x16s.
But if I have one graphics card in my x16 slot,
and I need to put in three different cards that are x1s,
I can still do that by putting two of them
into the x1 slot and the other x1 into the x16 slot.
Yes, the x1 will fit into an x16 slot,
and it will work.
Because that x16 slot will detect that it's only an x1,
it'll downgraded speed and only transmit information
to that x1 device using that part of the slot.
When you do this, we call this up-plugging,
because you're taking an x1 card
and putting it into an x4, x8 or x16 slot.
Now similarly, you can also do
what's known as down-plugging,
and this is kind of a weird concept.
But you can take an x16 card and put it into an x8,
an x4 or x1 slot.
Now when you do this,
that card must support that capability.
And it has to be able to actually fit into the slot.
If you can fit it into the slot,
the slot will still communicate with it,
but it will only work at x1 speeds.
So it'll be much slower than if you put it in the right slot
that it was designed for.
That said, I really don't recommend doing down-plugging
where you put that larger card in a smaller slot,
because it will have performance issues
for you because that card is expecting
the full bandwidth of it's designed slot type.
But there is really no issue
when you're doing up-plugging
and taking an x1 card and putting it in something
like an x16 because it will still operate
at the full x1 speeds because x16 can support x1.
But x1 can't go as fast as an x16 to support an x16 card
in an excellent slot.
Now the final type of expansion card
we need to talk about is what's known as a Mini PCIe.
And yes, this works just like a standard PCIe card
but it's a smaller form factor.
Instead of being a large expansion card
that you're going to use in a desktop or server,
instead with a Mini PCIe,
you can plug this into things like laptops.
Generally, you're going to find that Mini PCIe cards
are used inside of laptops,
specifically for things like wireless networking,
or providing a cellular modem capability for that device.
So with that said, what do you need to remember
about expansion cards?
Well, the first thing to remember
is that really in modern desktops,
the only type of expansion cards
you're really going to run across are going to be PCIe x1s
and PCIe x16s.
Most of the time, it's really hard to find an x4 or x8 port
on most modern motherboards,
and therefore there's not a lot of devices
or cards that are available for those form factors.
When you're looking at a PCIe x1 card,
it's very easy to identify
because the connector part of it is very small,
about the size of your thumbnail.
When you're looking at a PCIe x16 card on the other hand,
it has a very long connector
that's about six or eight inches.
When you go and plug one of these cards in,
you're simply going to line up the connector to the port,
push down and it will insert into place
and you'll feel click and that's going to hold it into place
and then you'll screw that card into the case
to make sure it doesn't move or wiggle
or move out of the socket.
When you're dealing with x1s cards,
they are much slower than x16 cards and x1 cards
are going to be used for things like modems,
networking cards, wireless cards,
audio cards and things like that.
Whereas an x16 card is generally going to be used
for graphics and video cards in 3D and gaming systems.