These days the usage of connecting slots has become very common. An expansion slot, otherwise referred to as a bus slot or expansion port, is a port or hardware connecting space located on the computer system’s motherboard.
They allow expansion cards to be connected to a computer system. Upgrading a motherboard can solve any incompatibility issues in a system.
But for the upgrade to occur, the types of slots on the motherboard should be known along with their replacement needs, i.e., whether a particular slot fits a particular replacement part. Things have changed; everyone has a different choice or needs regarding technological advances.
Keeping this in mind, various types of expansion slots are present today. PCI, PCI Express, AGP, ISA, AMR, CNR, EISA and VESA are the ones.
Key Takeaways
- PCI and PCI Express are two computer expansion slots connecting peripheral devices to a computer’s motherboard.
- PCI is an older technology and has a slower data transfer rate than PCI Express, which is faster and more efficient.
- While many newer computers only use PCI Express slots, some older devices may still require PCI slots, and compatibility between the two types can be an issue.
PCI vs PCI Express
PCI is an older standard that was first introduced in 1992. It is a parallel bus standard, meaning data is transmitted over multiple wires simultaneously. PCIe is a newer standard that was first introduced in 2003. It is a serial bus standard, meaning data is transmitted over a single wire at a time.
Comparison Table
| Parameter of Comparison | PCI | PCI Express |
|---|---|---|
| Origin | Introduced in 1992 by Intel. | Introduced in 2003 by Intel, Dell, HP and IBM. |
| Connection | Only connects hardware devices and graphics cards. | Whereas, it connects WiFi, graphic ports and others. |
| Speed | Slower as compared to PCI Express. | It is faster. |
| Data rate | Slower data rate. | Faster data rate. |
| Slot type | Standardized slots are present. | Slots depending upon the number of lanes, are present. |
| Bandwidth | 133 MB/s with 33 MHz, 206 MB/s with 66 MHz and 532 MB/s with 66 MHz. | Varies from 250 MB/s to several GB/s. |
| Features | It has a very limited amount of features. | It has more developed features than PCI. |
| Hot plugging | Not supported or optional. | Supported. |
What is PCI?
Peripheral Component Interconnect, or PCI, is an expansion slot in a computer system that connects hardware devices to the system. Initially introduced by Intel in 1992, PCI is the most commonly used expansion slot.
Otherwise known as Conventional PCI, it works on a parallel interface having a single bus standard. Devices that are connected to the PCI bus are first connected to their respective buses, and then they are allotted addresses.
PCI is either 32-bit or 64-bit in width, the latter being created after a few years. There are preferably three types of PCI bus that are used in common, i.e.,
PCI with 32-bit and 5V signal voltage, PCI with 64-bit and 5V signal voltage, and PCI with 64-bit and 3.3V signal voltage. The connection is made through a list of steps, i.e., receiving, supplying, sensing and then providing the PCI card.
Moreover, the original PCI does not need a hot-swappable bus, so the system power should be turned off whenever any card is inserted into or removed from the PCI slot.
What is PCI Express?
Peripheral Component Interconnect Express, or PCI Express, officially known as PCI-e, is a high-speed expansion slot used for connecting hardware devices and many more in a computer system. PCIe was first introduced by Intel, Dell, HP and IBM in 2003 to replace the PCI and bring improved changes.
The PCIe comes with a serial interface most commonly used in the expansion of laptop cards and computer storage. The current generations of PCIe are PCIe 1.0, PCIe 2.0, PCIe 3.0 and PCIe 4.0.
The bandwidth of PCIe, being 1 GB/s for each lane, tends to be doubled with each generation. PCIe turned out to be more compatible with the existing operating systems than PCI and is undoubtedly considered a better version.
The connection involves installing, connecting and transmitting the PCIe interface card. A DMA (Direct Memory Access) engine is compatible with the PCIe and, as a result, provides better performance and low occupancy if the commercial solutions cannot solve any problem.
Main Differences Between PCI and PCI Express
- PCI has an older parallel interface, whereas PCIe has a serial interface.
- PCI was introduced first in 1992, and PCI was introduced 11 years later in 2003.
- PCI can connect hardware devices, graphic cards, modems etc., while PCI can connect WiFi too.
- PCI is slower as compared to PCIe, and it even has a slower data rate.
- There are standardized slots present in PCI, while in PCIe, the slots depend upon the number of lanes present.
- Bandwidth in PCI is 133 MB/s, 206 MB/s and 532 MB/s. But in PCIe, it varies from 250 MB/s to several GB/s.
- Being the older version, PCI contains a very limited amount of features. PCIe is the updated one that has more developed features.
- The feature of hot plugging is supported only in PCIe and is optional in PCI.
- https://scholar.google.com/scholar?as_vis=1&q=pci+slot&hl=en&as_sdt=1,5#d=gs_qabs&u=%23p%3DCdOBznbN4dUJ
- https://ieeexplore.ieee.org/abstract/document/7111377
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Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.
