Can a standard cat5 cable transmit at a speed of 1000 Mbit/s ?

I've asked several people I know in the networking field and received different answers. I know a cat5 "works" on a Gigabit network but does it give the same performance of a cat5e or cat6 cable ?

6 Answers 6


You can use Cat5 for really short runs in a Gigabit environment, but it isn't recommended. Cat5e is fine in almost all scenarios, but if you're wiring from scratch, use Cat6, it's only fractionally more expensive.

Good Wikipedia info here - particularly the link about "far-end crosstalk".

  • 1
    When I renovated I even used Cat7 everywhere. Only 1.4 times as expensive as Cat5 (when buying 500 meters). Future proof too.
    – pi.
    May 27, 2009 at 13:27
  • I don't know what you mean by 'really short runs' but I have a ten-metre Cat5 cable from circa 2000 or earlier and it handles Gigabit flawlessly. Might just be luck though.
    – oals
    Aug 18, 2015 at 18:54
  • @pi. Just FYI, Cat7 does not exist in 2015 and did not exist in 2009. It's a manufacturer sham to drive sales.
    – oals
    Aug 18, 2015 at 18:56

Theoretically, CAT5 should suffice.

Practically, most switchs will require CAT5e or higher (CAT6 etc.) to work properly and will throttle back to 100m if you try to hook them up with CAT5 or low quality CAT5e cabling.

Higher spec cables are not expensive so most of the times I'd recommend the upgrade.


1000 Base T was designed for use on standard CAT5 cable, however CAT5E is recommended due to its tighter specifications. I'd have a read of the Wikipedia article on CAT5.

A Gigabit link might "come up" on a CAT5 cable, however you may notice increased retransmits on the interface, due to interference issues.

Definately possible, but not recommended.


Sure, you're not going to get optimal results with CAT5, but it's all about your situation.

  • If you've already got CAT5 run, and you have the budget for GB switches but not new cabling, get the switches, you'll see results
  • If you haven't run cable yet, get 5e or 6, without a doubt

It's going to work, without a doubt, but not as close to rated speed as you'd get with a higher grade of cable.


It isn't certified to give the same performance, no. The basic difference between a CAT5 and a CAT5e cable is that the CAT5e is certified to a higher standard than CAT5.

CAT5 won't give the same performance as CAT5e on a gigabit network, in short.


The 1000BASE-T standard was designed/intended to run over cat5. However it was discovered that there were some holes in the cat5 specification with the result that gigabit operation over cable that only marginally met the specs could not be gauranteed.

In practice it is very likely to work fine, especially if the actual run length is only a small fraction. of the maximum

Ethernet tends to be something of an all or nothing protocol. It doesn't rate adapt in the way that something like DSL does. If the signal integrity is bad then you will likely either start seeing packet loss or the connection will drop all the way back to 100M.

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