As data centers face the popularization of 40Gbps Ethernet, AI training clusters require TB-level data interaction per second, and ultra-high-definition video production demands real-time transmission of 16K footage, the 10Gbps limit of Category 6 cables has become inadequate, while the 10Gbps performance of Category 7 cables also falls short. At this point, Category 8 (Cat8) network cables, with their 40Gbps transmission capacity, have become a "must-have configuration" for high-end network scenarios. They are not an "excessive pursuit" for home users but a professional solution tailored for short-distance, ultra-high-speed data transmission, redefining performance standards for data center-level cabling.
Cat8 network cables are the latest twisted-pair category compliant with the TIA/EIA-568-C.2-1 (U.S. standard) and ISO/IEC 11801 (international standard). Officially released in 2016, their core positioning is to address the pain point of "short-distance high-speed connections within server racks" in data centers. Their structure features significant upgrades compared to Cat6 and Cat7 cables: adopting an S/FTP (Screened/Foil Twisted Pair) design with "double-layer shielding + pair-wise individual shielding" — the outer layer is a metal braided overall shield, and the inner layer is foil shielding for each pair of conductors. This dual protection maximizes isolation from external electromagnetic interference and crosstalk between pairs. The twisting density of the 4 pairs of copper conductors is over 30% higher than that of Cat6, with finer twist pitches (and different pitches for each pair), further reducing signal interference. The copper conductors mostly follow the 22AWG gauge (thicker than Cat6’s 23AWG) and are made of high-purity oxygen-free copper, offering far superior conductivity and signal stability to ordinary copper materials. The sheath is mainly made of LSZH (Low Smoke Zero Halogen) material, meeting the "low smoke, zero halogen" fire safety requirements of data centers and preventing the release of toxic gases in case of fire.
In terms of core performance, the "high-speed advantages" of Cat8 cables are highly targeted. In terms of transmission speed, their operating frequency reaches up to 2000MHz (8 times that of Cat6 and twice that of Cat7). They can stably support 40Gbps (40 Gigabit Ethernet) within a transmission distance of 30 meters, and even remain backward compatible with 10Gbps at 100 meters. This "short-distance high-speed" feature is perfectly suited for data center scenarios: the distance between top-of-rack switches and servers is usually ≤10 meters, and the distance between end-of-row switches and rack headers within the data center is ≤30 meters — both scenarios can fully leverage the 40Gbps peak performance of Cat8 cables, avoiding the issue of "wasting high-speed bandwidth on long-distance transmission." In terms of anti-interference capability, the S/FTP double-layer shielding design allows it to withstand strong electromagnetic environments: even when close to high-radiation equipment such as UPS power supplies and server clusters in data centers, the signal packet loss rate can still be controlled below 0.001% — a capability that Cat6 cables (relying solely on cross-shaped splines) and Cat7 cables (with single-layer shielding) cannot match. In terms of physical performance, the signal attenuation of Cat8 cables is 50% lower than that of Cat6; at 40Gbps, the attenuation within 30 meters is only ≤4.5dB, ensuring no signal distortion during high-speed transmission. It also supports PoE++ power supply (IEEE 802.3bt standard), which can deliver 60W of power to high-power devices (such as AI servers and high-definition PTZ cameras) via the cable, reducing the complexity of data center cabling.
The application scenarios of Cat8 cables are highly concentrated in "high-end professional fields" and have almost no overlap with home network needs. Data centers are their core battlefield: "intra-rack connections" between Top-of-Rack (ToR) switches and servers, and "short-distance interconnections" between End-of-Row (EoR) switches and rack headers all rely on Cat8 cables to achieve 40Gbps high-speed data interaction. For example, the new-generation data centers of Alibaba Cloud and Tencent Cloud have widely adopted Cat8 cables to support real-time computing power scheduling of cloud servers. The AI and supercomputing fields are also inseparable from them: in AI training clusters, GPU servers need to exchange dozens of gigabytes of training data per second, and the low latency (≤1 microsecond) of Cat8 cables prevents data congestion and ensures training efficiency. For short-distance connections between nodes in supercomputing centers, Cat8 cables are also commonly used to reduce cabling costs (cheaper and easier to maintain than fiber optics). In the ultra-high-definition video and broadcasting industry, scenarios such as 16K UHD live broadcasting and real-time rendering of film special effects require transmission of hundreds of megabytes of video streams per second — the 40Gbps bandwidth of Cat8 cables can easily handle this, avoiding picture stuttering or delays. Additionally, core trading systems of financial institutions (such as high-frequency stock trading) and real-time data acquisition systems of scientific research institutions also regard Cat8 cables as their first choice for cabling due to their strict requirements for speed and stability.
The installation of Cat8 cables must strictly follow "professional standards"; otherwise, their performance will be significantly compromised. First, control the bending radius: due to the outer metal braided shield, Cat8 cables are relatively thick and rigid (with a diameter of approximately 8-10mm), so the bending radius must be ≥8 times the cable diameter (about 64-80mm). Excessive bending will damage the shielding layer and twisted structure, leading to a sharp drop in anti-interference capability. Second, ground the shielding layer: "single-point grounding" or "multi-point grounding" standards must be adopted (designed according to the data center’s grounding system) to ensure reliable connection between the shielding layer and the grounding busbar. Poor grounding will turn the shielding layer into an "electromagnetic antenna," which instead amplifies interference. Third, use Cat8-specific connectors and patch cords: ordinary RJ45 connectors cannot adapt to its wire diameter and shielding design; TERA shielded connectors or Cat8 shielded RJ45 connectors must be used. During crimping, ensure tight contact between the shielding layer and the connector’s shield shell; the patch cord length is recommended to be ≤5 meters to avoid signal attenuation from excessive length. Finally, when routing cables, maintain a parallel distance of ≥50cm from high-voltage lines (such as 380V power lines). Although Cat8 has strong anti-interference capabilities, this further reduces potential interference risks.
When purchasing Cat8 cables, avoid the "fake Cat8" trap. First, check standard certifications: regular products must have UL (U.S.), CE (EU), or China 3C certifications, and clearly mark parameters such as "CAT8," "S/FTP," "40Gbps," and "2000MHz" on the sheath. Products without certifications or with vague parameters are mostly counterfeits. Second, inspect shielding integrity: after stripping the sheath, check whether the metal braid covers evenly without damage, and whether the foil shielding for each pair is intact. Discontinuous shielding layers directly affect anti-interference performance. Third, choose professional brands: prioritize brands deeply engaged in the cabling field, such as Panduit, CommScope, and Nissin. These brands’ Cat8 cables undergo strict testing and have high performance compliance rates. Avoid purchasing "low-cost no-name products" — they may use aluminum-clad copper instead of oxygen-free copper or reduce shielding layer density, failing to meet the 40Gbps transmission standard.
In conclusion, Cat8 cables are high-end cabling products "specialized for specific use." They are not an "upgrade option" for home users (home broadband currently maxes out at 2000Mbps, for which Cat6 is sufficient) but a "must-have configuration" for professional fields such as data centers, AI, and finance. When making a choice, clearly define your scenario needs: if you require short-distance high-speed transmission with extremely high stability, Cat8 is the optimal solution; if you need gigabit networks for homes or ordinary enterprises, Cat6 cables offer higher cost-effectiveness. A rational understanding of Cat8 cables’ positioning ensures that your wiring investment accurately matches actual needs.
