In other words only some of those old cat 5 cables are good enough to be cat 5e cables.
Cat 5 cable gigabit speed.
It was once believed that achieving gigabit speeds with ethernet would require the use of fiber optic cables or other special network cable technology.
More recently the introduction of cat 7a cable increases the speed to 1ghz and throughput to 40gbps but tops out at 165 feet.
Cat 6 and cat 6a cables are more interesting.
Category 5 cable cat 5 is a twisted pair cable for computer networks since 2001 the variant commonly in use is the category 5e specification cat 5e the cable standard provides performance of up to 100 mhz and is suitable for most varieties of ethernet over twisted pair up to 1000base t gigabit ethernet.
The new 2ghz speed limit finally category 8 is the new.
The old fashioned cat 5 cable is no longer a recognized standard but it technically supports gigabit speeds just not well.
The category 6 augmented cable standard or cat 6a was created to further improve the performance of cat 6 ethernet cables using cat 6a enables 10 gigabit ethernet data rates over a single cable run up to 328 feet.
If you have only tried a cat 5e cable you owe it to yourself to try a cat 6 cable.
Cat 6 supports 10 gigabit ethernet only up to 164 feet of cable length.
For most purposes gigabit ethernet works well using a regular ethernet cable specifically the cat5e and cat6 cabling standards.
Fortunately those are only necessary for long distances.
If you are having problems achieving gigabit speeds and you have cat 5e cables in the mix then it is safe to assume that those specific cat 5e cables are not gigabit capable.
Cat 5 is also used to carry other signals such as telephony and video.
Cat 5e cable is enhanced to reduce interference so that it can reliably.
This is almost certainly the issue.
If you have gigabit internet 1gbps an old ethernet cable will hold you back.