What is a PCI-E Card? The Different Between PCI vs PCI-X vs PCI-E

What is a PCI-E?

 

PCIe (Peripheral Component Interconnect Express) is a high-speed interface for efficient data transfer between electronic components. It is typically used in desktop, mobile, and server systems. It can also work in specific locations for other networked devices, such as set-top boxes and game consoles.

 

PCIe is a point-to-point connection that links PCIe-compliant devices on a motherboard to expansion cards or storage devices, such as SSDs or hard drives. PCIe connectors use differential signals to transfer data over individual copper pairs and can reach speeds of up to 16 GT/s.

 

For optimal performance and compatibility during transmission, the PCIe standard utilizes a variety of channel sizes to connect two or more components simultaneously, depending on the network's speed requirements. For example, more extensive lanes (e.g., x16) are generally used for devices with high bandwidth transfer requirements, such as graphics cards for high-resolution content. In comparison, smaller lanes (e.g., x1) are reserved for lower-speed peripheral devices (e.g., USB or SATA ports).

 

What is a PCIe Card, and How Does it Work?

 

PCIe card (also known as PCI Express card, PCIe-based card) is a network adapter with a PCIe interface for motherboard-level connectivity used as an expansion card interface. PCIe-based expansion cards, specifically, are designed to be inserted into PCIe slots on the motherboards of devices such as hosts, servers, and network switches, and most new PC motherboards today have PCIe slots for installing PCIe cards into the corresponding PCIe slots.

 

Rather than handling data from multiple sources like a bus, PCI Express cards can control where the data goes by enabling a series of point-to-point connections through a switch. When a PCIe card is inserted, a logical connection is created between the slot and the card to communicate, becoming an interconnect or link. Thus, a point-to-point data communication channel is realized between the two PCIe ports, allowing them both to send and receive common PCI requests and interrupts.

What is The Primary Use of PCIe Slot?

 

PCIe slots can also provide additional functionality to your system that might otherwise be limited due to a lack of available host space or power.

 

The most common uses for PCIe slots include storage upgrades via NVMe SSDs, upgrading an existing graphics card to provide gaming performance, connecting multiple monitors using a dedicated card, or expanding networking options with a PCI Ethernet adapter. It can also accommodate additional USB ports and allow you to add Thunderbolt 3 connectivity, which is becoming increasingly important for home and business users.

 

Other uses include connecting audio interfaces to record music using higher-quality sound equipment or installing specialized cards (RAID controllers or GPU gas pedals) for deep learning, AI training, and other tasks applied to large workloads. In conclusion, the PCIe slot is an ideal solution for improving your system for performance improvements or needing multiple ports and connectors.

The Difference Between PCI vs. PCI-X vs. PCI-E

 

The PCI standard has developed several improvements, embodied in the corresponding network card. The development process is that PCI card services for home and business users are gradually unable to meet the network demand. A PCI-X card is an enhanced version of the PCI for higher bandwidth requirements. The latest version of the PCI-E is the newest version of the current consumer and is the preferred choice for purchase.

 

The next part will introduce the difference between PCI vs. PCI-X vs. PCI-E.

 

Working Topology

 

The primary difference between the latest PCIe cards and the previous PCI cards and PCI-X cards is the data transmission method ''parallel vs. serial''. PCI and PCI-X network cards are designed using the original PCI standard, a classic shared bus architecture in which all peripherally linked devices use the same bus in parallel. During data transmission, data is sent and received over multiple lines simultaneously. Devices must wait on the bus while communicating with the computer, and the more devices you add, the more the overall performance decreases. PCI-E cards utilize a new point-to-point serial technology, similar to on-board networking, so each device is equipped with a separate bus, creating a more efficient bus system. A single serial connection with a higher clock speed can achieve the same data transfer rate as multiple parallel lines operating under the same roads.

 

Size of Slot

 

Slot sizes on computer motherboards are also very different between these three. Traditional PCI cards come in 32-bit and 64-bit versions for fixed widths, and PCI-X cards (which are only 64-bit wide) are physically similar to 64-bit PCI cards. Traditional PCI slots are 85mm long in the 32-bit version; most PCI-X cards use 130mm long 64-bit slots. Obviously, the slots and corresponding NICs take up considerable space. On the other hand, PCI-E cards can only be inserted into PCIe slots designed for them, the size of which depends on the number of lanes of the PCI-E bus, e.g., 'x1', 'x8', and so on. The number indicates the 'lanes' provided by the slot. PCI-E x1 slots have only one lane and take up almost no space on the motherboard, while 32-lane PCI-E x32 slots are similar in size to PCI-X slots.

 

Bandwidth

 

As mentioned earlier, PCI cards come in two different models, 32-bit and 64-bit, and they operate at 33MHz and 66MHz bandwidths respectively.The potential bandwidth is 133MB/s at 32-bit 33MHz standard, 266MB/s at 32-bit 66MHz or 64-bit 33MHz, and 533MB/s at 64-bit 66MHz. Most PCI-X network adapters are 64-bit and typically run at 66MHz, 100MHz, 133MHz, and up to 533MHz under PCI-X 2.0, with a maximum transfer rate of 1.06GB/s. On PCIe cards, the bandwidth is vastly improved, ranging from 250MB/s to several GB/s per lane, depending on the size and version of the card. PCIe 5.0 x1 has a maximum bandwidth of 3.938GB/s.

 

Why Do You Need a PCI-E Card?

 

Break Through the Bottleneck Than Predecessors

 

In terms of technology, the PCIe card abandons the traditional PCI. The PCI-X network card requires a complex alignment parallel transmission method and serial technology so that each channel has an independent bandwidth and will not interact with each other in the transmission process, reducing the interference of network transmission.

 

Ensure Effective Transmission

 

In terms of efficiency, the transmission rate of the PCIe card will not be reduced with the increase in the number of channels. Then, the user uses the PCIe card, even if the motherboard is mounted on more than one card, it will not affect the data transmission rate. If a PCI or PCI-X card is used, mounting more cards will reduce the original transfer rate, which is limited by the shared bus topology of these cards.

Offers an Economical Solution

 

On the cost side, the PCI Express network adapter's peer-to-peer transfer approach reduces system development and manufacturing costs because engineers have less difficulty designing the hardware platform.

 

PCI, PCI-X, and PCI-E cards coexist in the market today. However, based on the previously mentioned higher speeds of PCIe network cards and compatibility with current operating systems, computer designers and manufacturers continue to integrate PCIe into their newest products. As the technology develops, PCI-based cards will be gradually phased out, and PCI-E cards will have an increasing market share.

 

Conclusion

Requirements for network transmission rates and high-level software continue to promote breakthroughs in PCIe performance. Newly invented PCIe standards, as well as PCIe cards, the current PCI 4.x, PCIe 5.x, and the yet-to-be-born PCIe 6.x, are proving in the marketplace that they can close the development gap between PCIe-based cards and hosts, and that they have great potential for future network development.