Throughout the history of consumer computing, different expansion slots have been used . In them, as you well know, users could connect cards that expanded the functionality of our motherboards. At least before, because right now most boards integrate many of these old functionalities. We are going to see the different types of slots that have been used in our motherboards.
We have already talked about what an expansion card is and what it is for . As you well know, throughout the history of consumer computing, there have been different slots. Each of them served a specific type of this type of card. But, today, the vast majority of them are nothing more than a memory. Cards and slots such as AGP, PCI-X or ISA are nothing more than memories for the most veteran users of this world.
Slot or socket, what should you call them?
Actually both definitions are correct, so you can call it whatever you prefer. There are people who prefer to call these elements grooves because they are a female element in which another male element is inserted, and they also have an elongated shape. Although socket is not exactly a synonym for groove, it has been used in this type of element for many years and is therefore equally accepted.
Types of expansion slots
ISA slots
This type of slot was developed in 1981. IBM was the company in charge of creating it, to give service to its bus called “PC bus” . Years later, it would be renamed the “ISA bus” .
When they came on the market, the use of this type of expansion slot was complex. Since each card that was connected to it, had to be configured internally by the user. Configuration that had to be done by jumpers or manual switches on the surface of the card.
Luckily for users, in 1993 Intel and Microsoft released the “P’n’P ISA” standard . Thanks to him, these cards stopped requiring the use of physical manual configuration .
PCI slots
The replacement for the ISA slot was the one already known to all, the PCI slot. These slots began to be used in motherboards from the year 1993, when Intel introduced its PCI bus with its Intel Pentium processors .
As you can see in the previous photo, the size of this expansion slot model is much smaller than that of the old ISA slot.
The main problem with the PCI bus was that all its resources were shared among all its members. Which was a bottleneck when using cards that required higher bandwidth.
PCI-X slots
As a contemporary of the PCI slot, the PCI-X slot was also developed . We should not confuse these acronyms with PCI Express. The “X” in this case refers to “eXpanded” .
This type of slot was not widely used in the range of desktop motherboards. They were more oriented to server or workstation environments, since they allowed higher bandwidths than conventional PCI.
Just as PCI slots used 32-bit connectors, PCI-X use 32-bit or 64-bit connectors .
AGP slot
Introduced in 1996 by Intel for its Pentium P5 and P6 processors, this slot is the successor to the original PCI. Except that its use was exclusively intended to be used by graphics cards of the time.
As this is a dedicated 66 MHz bus , now the graphics cards already had all the bandwidth they needed for proper operation.
PCI Express slot
This type of expansion slot is already well known to any computer user. It is the evolution of the old PCI cards that we mentioned before. It began to be used in 2005, gradually replacing the rest of the expansion slot models
Since this data bus does not share bandwidth between peripherals. Rather, each slot establishes a “point-to-point” communication . It doesn’t suffer from the problems that have always plagued the old PCI bus.
