Network Cables That Reduce Performance
If your home or office Ethernet (wired) network is now running at Gigabit speeds (1000Mbps), it’s time to unload your existing inventory of CAT5 network cables. While CAT5, CAT5e and CAT6 all use RJ-45 connectors, only CAT5e and CAT6 are designed for Gigabit Ethernet (CAT5 is designed for 100Mbps Fast Ethernet and the now-obsolete 10Mbps Ethernet standards). By replacing existing CAT5 cable with CAT5e or CAT6, you can improve the real-world performance of your network because using CAT5e or CAT6 cable provides better signal quality at Gigabit speeds.
How can you tell the difference between CAT5, CAT5e, and CAT6? Check the cable itself. Most network cables are marked with the standard they support (see Figure 3).

Figure 3 Markings on a typical CAT5e network cable.