Network Interface Cards (NICs), also known as network adapter cards, ethernet cards or network interface controllers, are crucial for modern networking requirements and are used in a wide range of applications from desktop PCs to high performance computing (HPC) and AI data centres.
There are many different form factors and standards of NICs, with most modern systems using PCIe or OCP 3.0. This article will delve into the key differences between them including use cases, functionality and physical architecture to help you understand which type best fits your working environment.
What is PCIe (Peripheral Component Interconnect Express)?
A PCIe slot is a general purpose expansion interface used to enhance the performance of a computer system through additional or improved functionality. NICs are an example of one type of compatible card, but Graphics Processing Units (GPUs), storage controller cards and other hardware also utilise PCIe slots.
A PCIe lane refers to a single data channel used for communication between the PCIe card and the motherboard. The total number of lanes, otherwise referred to as ‘bus width’, determines the maximum bandwidth for communication – the higher the lane count, the higher the bandwidth. PCIe NICs come in x1, x4, x8 or x16 bus widths.
PCIe NICs
PCIe is the most common NIC form factor in today’s enterprise servers, offering high flexibility and broad compatibility with range of data speed options. They support simple plug and play installation and can be used in almost any modern system with an available PCIe slot. The wide range of bus widths and data rate options makes them a good choice for a variety of workloads.
Since its launch following PCI-X, several PCIe standards have been introduced each significantly increasing available bandwidth:
|
Generation |
Launched |
x1 Lane Bandwidth |
X16 Lane Bandwidth |
|
PCIe 1.0/1.1 |
2003 (1.0)/2005 (1.1) |
250Mbps |
4Gbps |
|
PCIe 2.0 |
2007 |
500Mbps |
8Gbps |
|
PCIe 3.0 |
2010 |
1Gbps |
16Gbps |
|
PCIe 4.0 |
2017 |
2Gbps |
32Gbps |
|
PCIe 5.0 |
2019 |
4Gbps |
64Gbps |
|
PCIe 6.0 |
2022 |
8Gbps |
128Gbps |
|
PCIe 7.0 |
Specification released late 2025 |
16Gbps |
256Gbps |
All generations offer full backward compatibility, enabling incremental system upgrades without big infrastructure overhauls. PCIe 3.0 and 4.0 remain the most common in most enterprise networks, while later generations are mainly utilised in high performance computing, AI and hyperscale datacentres.
What is OCP (Open Compute Project)?
The Open Compute Project is not an official standards body, but a collaborative open-source initiative founded by Meta (formally Facebook) and other leading tech companies, aiming to address exponentially growing data centre demands. The OCP standard is not a direct replacement to PCIe in the way that PCIe succeeded PCI and PCI-X. Instead, it acts as a complimentary standard designed to address specific challenges associated with using PCIe NICs in dense high performance environments.
OCP NICs offer a standardised design to improve energy efficiency, thermal management, serviceability and bandwidth density in modern data centres. They are connected via a dedicated OCP mezzanine on the front or rear of the server chassis and are designed to be hot swappable during live server operation.
Key advantages in high density computing management include:
- Hot swap capability – Cards can be replaced during server operation, minimising maintenance downtime
- Serviceability - external access for easy maintenance without shutting down the whole system
- Improved Thermal Management – Optimises airflow and compatible with both air and liquid cooling systems
- Space Efficiency – Frees up internal PCIe slots for other expansion devices
- High Bandwidth Support – 25GbE to 400GbE suitable for AI training, cloud computing and edge deployments
OCP 3.0 Form Factors
OCP 3.0 NICs come in three main form factors:
- SFF (Small Form Factor) - Compact form factor standard for OCP 3.0 slots supporting up to x16 PCIe lanes
- TSFF (Tall Small Form Factor) - Same width and height dimensions as SFF but with added clearance for improved airflow and heat dissipation
- LFF (Large Form Factor) - Wide form factor requiring 2 free OCP ports with wider heat sinks for improved heat dissipation. An uncommon form factor that supports 2 lots of x16 PCIe lanes with the additional OCP port.
Choosing the Right NIC Standard
The appropriate NIC standard for your requirements will depend on server architecture and workload, PCIe slot availability requirements and future expansion expectations. It is worth noting that not all servers support OCP technology, so it is important to check the specifications of existing hardware.
PCIe
PCIe NICs are best suited to general purpose servers, workstations and most common enterprise applications. They offer broad compatibility and strong performance for any system with a PCIe slot and generally remain the more cost effective option.
- Uses standard PCIe ports
- Great performance and compatibility over a wide range of systems
- Internal access required for modifications, upgrades and replacements – requires server downtime and workflow interruption
- Easy modular upgrades using existing PCIe slots
OCP
OCP NICs excel in hyperscale and high density data centres, helping to reduce cable clutter, simplify maintenance and add efficiency to cooling and heat dissipation through heightened control over chassis design. Their hot swap capabilities make them useful in high risk applications where significant maintenance downtime can have huge impacts on system and business performance.
- Hot swappable port simplifies maintenance and avoids costly server downtime
- Improved airflow and heat dissipation for dense racks
- Higher port density speeds
- Frees up PCIe slots
ATGBICS Solutions
ATGBICS has introduced an ever-expanding portfolio of Network Interface Cards including PCIe up to 4.0 and OCP 3.0 standards with a range of bus widths, data rates, and form factor compatibility. We offer single, dual or quad-port options for flexible connectivity up to 200Gbps and compatibility with both Windows and Linux.
All our products come with a compatibility guarantee and lifetime replacement warranty for added peace of mind.
