Cat8 vs Fiber: Which one is best for you?

Cat8 vs Fiber: Which one is best for you?

Written by Don Schultz, trueCABLE Senior Technical Advisor, Fluke Networks Copper/Fiber CCTT, BICSI INST1, INSTC, INSTF Certified


In today's rapidly advancing technological landscape, the debate of Cat8 vs fiber optic for your networking needs is more relevant than ever. Cat8, a recent addition to the copper cable lineage, stands out for providing high-speed connectivity with a notable transmission frequency of 2GHz. On the other side, fiber optics, renowned for its pivotal role in elite data transmission, showcases unparalleled capacity in transmitting vast quantities of data across long distances at remarkable speeds. The dilemma between choosing Cat8 and fiber optics ultimately boils down to assessing your immediate requirements and future aspirations regarding cost, performance, and scalability.

As we delve into the specifics, it's paramount to understand what each technology offers. Cat8 Ethernet cable is a copper twisted pair Category cable that the industry already understands and knows. Its main feature, aside from high speeds, is familiarity which reduces the need for additional tools and training. Conversely, fiber optic cable has been a cornerstone in establishments demanding high speeds, low latency, networking over long distances, and robust performance. That said, fiber optic used for Ethernet may require unfamiliar tools, termination techniques, and expensive training. This comparative analysis will guide you through a detailed exploration of Cat8 vs fiber optics in terms of speed, bandwidth, cost, and installation, empowering you to make a well-informed decision tailored to your unique networking requirements.

Cat8 Overview

What is Cat8 Ethernet cable? Well, Cat8 is the natural evolution of Ethernet copper twisted pair Category cable that has been evolving for decades. The latest advancement in the copper cable family, codified by ANSI/TIA in 2018. What is Cat8 used for? Technically it can be used for any local area network (LAN) that requires copper cable designed to carry Ethernet packets. More specifically, Cat8 is designed to meet the escalating demands of high-speed networking. It's crucial to understand the capabilities and features of Cat8 to determine its suitability for your networking needs. Here’s a breakdown of its key attributes:

High-Speed Performance and Compatibility:

  • Networking Capabilities: How fast is Cat8? Cat8 is engineered to handle 25G and 40G networking demands efficiently at distances up to 30 meters (98 feet). After 98 feet, Cat8 operates at 10G maximum speed which makes it functionally equivalent to Cat6A over longer distances.
  • Frequency and Data Rate: It operates at a remarkable frequency of 2GHz, which is 4 times faster than its predecessor, Cat6A. That’s only up to 98 feet, though.
  • Compatibility: Designed to be forward and reverse compatible with 1G, 2.5G, 5G, 10G, 25G, and 40G networking equipment, Cat8 ensures seamless integration with existing infrastructure. The use of copper Ethernet patch panels, keystone jacks, field termination plugs, and even 8P8C (aka RJ45s) further enhances its compatibility with a wide range of networking devices.

Technical Specifications:

  • Connectors and Shielding: Cat8, despite its fast operating speed capability, is not required to be shielded per ANSI/TIA 568-2.D. That said, Cat8 Ethernet is typically seen as shielded cable, with individually foil shielded twisted pairs in addition to wire braid shielding (S/FTP), providing maximum protection from ANEXT interference (alien crosstalk interference). Connectivity hardware is familiar, but patch panels and/or keystone jacks must be Category rated for Cat8 to achieve the desired performance.
  • Physical Characteristics: Cat8 Ethernet cable can technically possess any cable jacket type depending upon the environment but is typically seen with riser (CMR) or plenum (CMP) rated cable jackets. CM and/or CMG (general communications) cable jackets may also be seen, usually in stranded copper patch cord applications. Cat8 structure cabling is constructed with solid copper conductors of 24 to 22AWG like any other Category of Ethernet cable, utilizing eight conductors twisted into four pairs. The T568A or T568B color code termination requirements remain the same.


Typical example of Cat8 S/FTP Ethernet cable
Image Credit: Home Depot


Cost-Effectiveness and Practical Applications:

  • Affordability: Compared to fiber optics, Cat8 may be more cost-effective due to its copper-based nature, eliminating the need for fiber transceivers and the Ethernet switches that can leverage transceivers. That said, Ethernet switches capable of operating at 25G or 40G over copper are required to fully utilize Cat8, and those Ethernet switches are typically extremely expensive.
  • Ideal Use Cases: Best suited for data centers and server rooms where drops are 98 feet or less. Cat8 excels in environments that are transitioning to accommodate higher data loads over short distances. A key advantage of copper Category cable like Cat8 is support for Power over Ethernet (PoE) technology, allowing for space-saving installations.

Understanding these specifications and features of Cat8 can help you assess its suitability for your networking infrastructure, especially if you're aiming for high-speed data transmission over relatively short distances.

Fiber Optics Overview

What is fiber optic cable? Fiber optics, a cornerstone in the realm of data transmission, brings unparalleled efficiency and performance to networking and telecommunications. Here's a closer look at what makes fiber optics a revolutionary choice for high-speed, reliable data transfer:

Core Composition and Transmission Method:

  • Fiber optics transmit data as light pulses through strands of glass or plastic fibers, encapsulating the core technology that enables its high-speed capabilities.
  • Each fiber optic cable consists of multiple layers: the core, cladding, buffer tube, and jacket, with the core and cladding playing critical roles in guiding light pulses via total internal reflection.
  • This method of transmission allows for minimal signal loss over long distances, making fiber optics ideal for applications requiring extensive reach and high bandwidth.

Types and Applications:

  • Single-Mode Fiber (SMF): Utilizes a smaller core diameter to minimize attenuation, enhancing its suitability for longer distances and higher bandwidth applications. SMF cables are categorized into OS1 and OS2, with OS2 offering advanced capabilities.
  • Multimode Fiber (MMF): Features a larger core, allowing for the transmission of multiple modes of light. This design increases data throughput but can introduce signal loss and interference over longer distances. MMF cables are classified into OM1, OM2, OM3, OM4, and OM5, with OM3 and OM4 being the most prevalent for 40G networking. Please see Single mode vs Multimode Fiber Optic Cable for detailed information regarding the differences between SMF and MMF.
  • What is fiber optic cable used for? Fiber optics are extensively used across various sectors, including internet and cable TV, telecommunications, medical diagnostics, military and space operations, and undersea communications, demonstrating its versatility and reliability.


basic construction of a fiber optic cable

Basic construction of a fiber optic cable

Image Credit:  Electrical Engineering Portal (EEP)


Advantages Over Copper Cables:

  • Bandwidth and Speed: Fiber optic cables offer significantly higher bandwidth and speed compared to copper cables, including Cat8, making them capable of supporting data-intensive applications like 4K and 8K streaming.
  • Installation and Maintenance: Despite common misconceptions, fiber optic cables are easier and quicker to install than many would assume. Termination, given the proper tools and training, is not significantly more difficult than termination of copper twisted pair Category cable. Their smaller diameter and higher pull rating allow for more flexible deployment options, and they require less maintenance over time.
  • Cost-Effectiveness: Fiber optic cables are more affordable than many assume, especially when considering their longevity and the reduced need for replacements. The cost of fiber optic cables, connectors, and accessories has decreased as their use in low-voltage installations has become more common.
  • No worries about EMI/RFI: Fiber optic cables are immune to common sources of interference.
  • No issues with ground loops: Due to the nature of fiber, there is no danger of a ground loop forming when multiple AC electrical systems (or unequalized points of ground) are involved. This eases building to building backbone installations, as copper cable of any kind installed between two structures may introduce unforeseen problems unless careful attention is paid to the installation.

For a more in-depth discussion around these factors, please see Top 5 Advantages of Fiber Optic Cable for more information.

In summary, fiber optical cable stands out for offering a future-proof solution for evolving networking demands, allowing high-speed, long-distance data transmission. Fiber’s ability to transmit data with minimal loss, coupled with their resistance to electromagnetic interference, makes fiber optic a optimal choice for a wide range of applications.

Comparative Analysis: Speed and Bandwidth

When considering the speed and bandwidth capabilities of Cat8 and fiber optic cables for your networking needs, it's crucial to align your choice with the specific requirements of your network environment. Here's a comparative analysis focusing on these critical aspects:

Speed and Distance:

  • Cat8: Capable of transmitting 25 GB and 40 GB speeds up to 98 feet, Cat8 is a robust option for short-distance, high-speed requirements. This makes it particularly suitable for data centers where such distances are common, providing a cost-effective alternative to fiber optics in specific scenarios.
  • Fiber Optics: Preferred for its ability to maintain high-speed data transmission over longer distances, fiber optics is the go-to choice for networks that span across larger areas or require data to be transmitted between different buildings or locations. Its core technology allows for minimal signal loss, ensuring reliable data transmission even over vast distances.

Data Transfer Rate:

  • Cat8 can transmit 2 billion signals per second, showcasing a data transfer rate that can be 250-400 times faster than Cat5e. This significant leap in performance positions Cat8 as a powerful contender for environments that demand ultra-fast data transmission, albeit within its distance limitations.



*Note that these distances are “up to”. The type of light emitter, number of splices, and connectors affects this too!

**Cat6A distances are at 68℉ or less. Higher ambient temperature will shorten permitted run length.


Understanding these distinctions is pivotal in determining which cabling solution best fits your networking demands. While Cat8 offers an impressive speed and bandwidth capacity that could replace fiber optic cabling in certain data center configurations, the choice ultimately hinges on the specific network architecture, including distance requirements and the need for future scalability. Fiber optics, with its superior long-distance capabilities and high-speed performance, remains indispensable for extensive networks and applications where distance and reliability are paramount.

Comparative Analysis: Cost and Installation

When evaluating the cost and installation aspects of Cat8 versus fiber optics, several factors come into play that can influence your decision based on budget, application, and future scalability. Here's a breakdown to help you navigate these considerations:

Cost Considerations and Initial Investment:

  • Cat8 cables are recognized for their affordability, especially for 40G applications. This makes Cat8 a cost-effective choice for setups requiring high-speed networking over shorter distances.
  • Fiber optics, on the other hand, entail a higher initial cost, primarily due to the need for specialized equipment like conversion boxes. However, they offer a future-proof solution capable of scaling to 100G or 400G, which could result in cost savings over time.

Equipment and Installation:

  • Cat8 utilizes commonly available connectors, familiar in most networking environments, which may lower installation costs and complexity. Additionally, Cat8 can be sourced with Class II non-RJ45 connections for specific requirements.
  • Fiber optics require a different set of plugs, termination tools, splicing tools, and potentially expensive conversion boxes at each workstation for operation, potentially increasing the upfront cost. Despite this, the cables themselves are generally cheaper than Cat8, balancing the overall investment.

Installation and Maintenance

How do the installation processes and challenges differ between Cat8 and fiber optic cables?

Ease of Installation:

  • Cat8 is heralded for its ease of installation, particularly in environments already equipped with copper-based networking infrastructure. It's more readily available and doesn't require the specialized knowledge often associated with fiber optic installation.
  • Fiber optic cables, while perceived as more complex to install, offer flexibility and efficiency once in place. They are immune to electrical interference, a significant advantage in environments where this could be a concern.

Longevity and Repair:

  • Fiber optics have an edge in durability and repairability. Unlike Cat8, which cannot be repaired mid-cable underground, fiber optic cables can be mended, potentially reducing long-term maintenance costs.
  • The susceptibility of Cat8 to electrical interference and its limitation in repairability might necessitate more frequent replacements or upgrades, especially in harsher environments.

The choice between Cat8 and fiber optics extends beyond mere performance metrics to encompass cost, ease of installation, and future scalability. While Cat8 offers a cost-effective solution for high-speed, short-distance applications, fiber optics provide a robust, future-proof infrastructure capable of supporting the next generation of networking demands. Your decision should align with both current requirements and anticipated future needs, ensuring a balanced approach to performance, cost, and scalability.

Frequently Asked Questions

As you weigh the benefits of Cat8 and fiber optic cables, you likely have questions about their core differences, advantages, and use cases. This FAQ section addresses the most common inquiries to help you make an informed decision tailored to your networking needs.

What is Cat8 cable, and how does it differ from previous Ethernet cable standards?

When it comes down to it, Cat8 is not significantly different (physically speaking) from Cat6 or Cat6A. What defines a Cat8 cable from lower Categories is the speeds it is rated to achieve. Higher speeds are achieved with tighter pair twist rates, thicker cable jackets, thicker conductor insulation, and in the case of Cat8 the frequent use of individually shielded conductor pairs for internal cable crosstalk prevention.

What are the advantages and disadvantages of using Cat8 cables compared to fiber optic cables?

Cat8 Ethernet cable, at its core, is copper twisted pair Category cable with all of the limitations imposed upon any other Ethernet cable such as sensitivity to strong EMI/RFI sources, limitations on length imposed by ambient temperature, and a maximum 98 foot length if Cat8 is to be used at the best speed it can attain. Fiber optic cable cables, while also having far longer length limitations, don’t suffer from ambient temperature rise nor strong EMI/RFI sources. Glass is a stable material, making it an ideal transmission medium for long distance data transmission (think THOUSANDS of feet) and/or long distance data transmission at very high speeds in very harsh environments.

When does it make sense for a business or organization to switch from Cat8 to fiber optic cables?

The decision to switch from Cat8 to fiber optic cable is often one that is dictated by the equipment that will be used in the business and budget. Most businesses will install “dark fiber” for future use alongside copper twisted pair Ethernet cable like Cat6A. That all said, when bandwidth needs exceed 10G and the distances go past 328 feet it is a good time to start considering fiber optical cable right now (especially for building to building backbone drops). Cat8 is essentially a transition solution, and a temporary one with a questionable future. It makes much more sense to install less expensive Cat6A and dark fiber alongside it if future considerations are paramount.

What are the scalability and future-proofing considerations for each cable type?

It is clear that the middle to long term future belongs to fiber optical cable. It scales much higher and farther than any Category copper cable. Considering the low cost of running fiber optical cable, installing “dark fiber” (unused fiber) with live copper twisted pair drops is a good idea. The only question is…which fiber should be run for future use? At the moment, SMF (single mode fiber) is the best on offer but that may change as the technology develops further. It is a mild gamble, but likely worth it down the road.

How do Cat8 and fiber optic cables differ in terms of distance limitations and signal attenuation?

Cat8 is essentially Cat6A with the ability to transmit up to 40G up to 98 feet. After 98 feet, signal attenuation drops the signal back to 10G. The maximum distance for any copper Ethernet cable, Cat8 included but at 10G, is 328 feet under the best of circumstances. Temperatures and EMI/RFI issues may reduce the 328 feet maximum to much shorter lengths. Fiber optic cables, in the case of OM4 MMF for example, can carry 10G to 1,800 feet or 100G to 410 feet with no worries about temperature and EMI/RFI limitations affecting the signal and therefore length maximums.

Final Thoughts

Throughout this discussion, we have extensively explored the distinctive attributes and applications of Cat8 and fiber optic cables, delineating each’s proficiency in addressing varying networking demands. Cat8 emerges as a cost-efficient, high-speed solution suited to environments where data transmission over short distances is prioritized, highlighted by its remarkable bandwidth, ease of installation, and compatibility with current networking frameworks. In contrast, the future-ready fiber optics stand out for their unmatched capability in delivering high-speed data over long distances, exhibiting minimal signal loss and immunity to electromagnetic interference, providing a scalable solution that caters to expansive network infrastructures and demanding data transmission requirements.

As we weigh the merits of Cat8 against those of fiber optics, it becomes clear that the ultimate selection hinges on a balanced consideration of immediate networking needs, cost implications, and forward-looking infrastructure goals. Whether prioritizing the affordability and high-speed performance of Cat8 for short-range applications or the extensive reach and future scalability offered by fiber optics, the decision must reflect a strategic alignment with both present and anticipated networking landscapes. This choice, thereby, not only addresses current technological requisites but also secures a foundation for navigating the evolving demands of tomorrow's digital ecosystems.



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