How to choose a ethernet cables
Updated June 2026Independently researchedNo paid placement.
Choose a Cat 8 cable if you need the fastest speeds for short data‑center runs or future‑proofing, but for most homes a Cat 6a is plenty. Flat cables save space but can sacrifice shielding and durability; buy a flat cable only if you must run it under a rug or along a wall where bulk is a problem.
What is Cat 8 and who actually needs it?
Cat 8 is the fastest current Ethernet standard, supporting speeds of 25 or 40 Gbps over distances up to 30 meters. It requires heavy shielding (S/FTP) and is designed primarily for data centers, server rooms, or short‑distance backhaul links where massive bandwidth is essential. For a typical home user streaming video, gaming, or video‑calling, Cat 8 is massive overkill and often several times more expensive than Cat 6a. The cable itself is thick, stiff, and difficult to route around corners or through walls. Unless you run a home lab with 25 GbE gear or plan to keep your cabling for a decade without upgrading, Cat 6a is the smarter buy.
Cat 8 vs Cat 6a vs Cat 7 – how to decide?
Cat 6a is the sweet spot for most buyers: it handles 10 Gbps up to 100 meters, uses standard RJ45 connectors, and is widely compatible with current routers and switches. Cat 7 was never a true IEEE standard and uses non‑standard GG45 or TERA connectors; it’s largely obsolete and offers no advantage over Cat 6a for practical residential use. Cat 8 is the only option that reaches 40 Gbps, but its 30‑meter limit means you cannot run it across a large house. For ordinary gigabit internet, even Cat 5e works fine. Focus on your actual network speed and distance rather than chasing the highest number on the box.
Flat ethernet cables – convenience vs performance
Flat cables are designed for easy concealment: they slip under rugs, along baseboards, or behind furniture without bulging. Their thin profile makes them popular for temporary setups or renters who cannot run cable through walls. However, flat cables are almost always unshielded (UTP) and use a ribbon construction that is more prone to crosstalk and signal loss, especially over longer runs or near power lines. If you need 10 GbE or a run longer than 50 feet, a round, shielded Cat 6a cable is far more reliable. Use flat cables only for short, low‑speed runs where physical space is the top priority.
Shielding matters: S/FTP, U/FTP, and why Cat 8 is always shielded
Ethernet cables come in different shielding types: UTP (unshielded), FTP (foil shield), STP (braid shield), and S/FTP (braid plus foil). Cat 8 cables are required to be S/FTP to meet the 40 GbE specification, meaning they have both an overall braid and individual foil wraps around each twisted pair. That heavy shielding protects against interference but makes the cable stiff and adds cost. It also requires proper grounding at both ends, if your equipment lacks grounded ports, the shield may actually act as an antenna and worsen performance. For most home environments with low electrical noise, a quality Cat 6a UTP or FTP cable is perfectly adequate and much easier to handle.
Price and value – what you really pay for
Cat 8 cables command a significant premium over Cat 6a, often costing three to five times as much per foot. A large part of that price goes into the high‑grade shielding, more precise manufacturing tolerances, and certification costs. Flat cables, on the other hand, are among the cheapest options because they use minimal copper and simple construction. That low cost can be tempting, but cheap flat cables are often made with copper‑clad aluminum (CCA) rather than solid or stranded pure copper. CCA is brittle and carries signal poorly over distance. Always check the fine print: if the cable doesn’t specify “pure bare copper,” it’s likely CCA and should be avoided for any serious network use.
How to choose the right length and connector
Length matters more than most people realize. For Cat 8, keeping runs under 30 meters is mandatory to reach full speed; beyond that, the signal degrades to lower rates. For flat cables, longer runs increase crosstalk and signal loss, so keep them to 15 meters or less for reliable performance. Connector quality is equally important. Look for gold‑plated pins (which resist corrosion) and shielded connectors if you’re using shielded cable. Avoid cables with molded, unbooted connectors that cannot be removed, those can get stuck in ports and are a pain to replace. A snagless boot design is a nice extra for tight spaces.
Frequently asked questions
Can I use a Cat 8 cable with my existing router?
Yes, Cat 8 is fully backward compatible with any device that has an RJ45 Ethernet port. It will automatically operate at the highest common speed, usually 1 GbE on a typical home router. You won’t see any speed benefit unless both ends support 25 GbE or 40 GbE.
Do flat ethernet cables cause slower speeds?
They can, especially if they are unshielded and run parallel to power cables or over long distances. For short runs (e.g., a few meters between a modem and router), the speed difference is usually negligible. For longer or high‑speed connections, a round shielded cable is far more reliable.
What’s the maximum length for Cat 8?
The official IEEE standard limits Cat 8 to 30 meters (about 98 feet) for full 25 GbE or 40 GbE performance. Longer runs may still work but will drop to lower speeds, such as 10 GbE or 1 GbE, depending on cable quality and environment.
Is Cat 8 backward compatible with older devices?
Yes. Cat 8 uses the same RJ45 connector as Cat 5e, Cat 6, and Cat 6a. It will work with any Ethernet port, though the connection will run at the port’s maximum supported speed, no faster.
Why is my flat cable so stiff?
Some flat cables use solid copper conductors, which are less flexible than stranded conductors. Stranded flat cables are more pliable but are more prone to signal loss over distance. If flexibility matters, look for a cable that explicitly says “stranded” or “high‑flexibility.”
Do I need grounded connectors for Cat 8?
For full shielding performance, yes. If you use a shielded Cat 8 cable with ungrounded connectors, the shield can pick up interference and actually degrade the signal. Most consumer routers and switches do not have grounded Ethernet ports, so in many homes, the shielding of Cat 8 provides no real benefit.