Using a Cat8 Ethernet cable can improve the speed and performance of your local network (LAN) connections, but it will not directly improve your internet speed unless your internet service provider (ISP) is providing speeds close to or above what your current Ethernet cable can handle. Here’s why:

1. Internet Speed vs. Network Speed:

Internet speed is determined by your ISP plan. For example, if you're subscribed to a 100 Mbps or 1 Gbps plan, that’s the maximum speed you can get from your ISP.

Network speed is the speed at which devices on your local network communicate with each other (e.g., between your router, computers, or other devices).

Cat8 offers speeds up to 40 Gbps, but most home internet connections are far slower than that. Even gigabit internet (1 Gbps) doesn’t come close to utilizing the full potential of Cat8. So, if your internet plan is slower than the cable's capabilities, upgrading to Cat8 will not change your internet speed.

2. When Cat8 Helps:

High-Speed Local Transfers: If you’re transferring large files between devices on your network (like from one computer to a network-attached storage (NAS) device), Cat8 can improve the speed of those local data transfers, especially for things like backing up files, streaming high-quality media, or gaming on a LAN.

Future-Proofing: If your ISP provides multi-gigabit internet (e.g., 10 Gbps), or if you expect to upgrade to such speeds in the future, a Cat8 cable could help you achieve the maximum possible internet speed.

3. Router and Modem Limitations:

Even if you upgrade to Cat8, you’ll also need a router and modem that support the speeds you're aiming for. Most consumer routers and modems are designed for gigabit internet, so unless your equipment can handle 10 Gbps or higher, you won’t see a benefit from Cat8 for internet speed.

4. Real-World Use Cases:

For most home users, a Cat6 or Cat6a cable is more than enough to handle typical internet speeds, even up to 1 Gbps.

Cat8 is overkill unless you're working in a high-performance environment, like a data center or enterprise network, or have an internet connection faster than 1 Gbps (e.g., 10 Gbps or higher).

Conclusion:

Cat8 will not improve your internet speed unless your internet plan and networking hardware (router, modem) support speeds beyond what your current cable can handle (e.g., above 1 Gbps).

It can, however, improve internal network performance, such as file transfers or gaming over a local network, if other equipment is also high-speed compatible.