What is the max speed of CAT5e?

mikegg

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Jan 30, 2010
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I know the specs say it's designed for 1 Gbps has anyone ever tested whether it can do more?

IE. Can it do 4 Gbps? 5 Gbps? Up to 10 Gbps? Any real tests that show this?
 

Fardringle

Diamond Member
Oct 23, 2000
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Cable quality and length have a large impact on the answer to your question. Testing under controlled conditions has shown that it's possible to establish a gigabit connection using metal wire clothes hangers (instead of stranded patch cables) over short distances...
 

Gryz

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Aug 28, 2010
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I know the specs say it's designed for 1 Gbps has anyone ever tested whether it can do more?

IE. Can it do 4 Gbps? 5 Gbps? Up to 10 Gbps? Any real tests that show this?
Ethernet is not WiFi. Nor ADSL.

With WiFi (and with ADSL), both sides do a little testing to see what speeds are manageable without too much bit-errors and frame-drops. And then they settle at a particular speed.

With Ethernet, it's simpler. The speed is fixed. There are different generations of Ethernet. 10 Mbps, 100 Mbps, 1 Gbps, 10 Gbps, 40 Gbps and 100 Gbps. Both sides can do one or more of those speeds. There might be a little auto-negotiation to see which speed the cards on both sides support. And then they transmit at the highest speed both cards can do.

If the cable between the two isn't good enough, there will be bit-errors. And maybe frame-drops. But both sides keep transmitting at the same speed. They won't adapt. The won't go from 10 Gbps to 7 Gbps and then to 3 Gbps to see if that gives less errors.

Another thing you should understand: the speed that is guaranteed for a particular type of cable is for a specific maximum distance.
Example: 1 Gbps over Cat-5e is supposed to work over 100 meters max.
https://en.wikipedia.org/wiki/Category_5_cable#Maximum_cable_segment_length
Another example: 10 Gbps over Cat-6 is supposed to not go over 55 meters max.
https://en.wikipedia.org/wiki/Category_6_cable#Maximum_length

So can you do 10 Gbps over Cat-5E ? Probably if your cable is only 10 meters long. Longer ? I don't know. A little googling gave me this page:
http://www.kit-communications.com/FAQCat5evsCat6.htm
The claim here is cat-5e can do 45 meters 10 Gbps.
Cat5e:
Gigabit Ethernet up to 100 meters
10 Gigabit Ethernet up to 45 meters
Cat6:
Gigabit Ethernet up to 100 meters
10 Gigabit Ethernet up to 55 meters
Cat6a:
Gigabit Ethernet up to 100 meters
10 Gigabit Ethernet up to 100 meters
If that is true, that's good news. I got cat-5e under the floor (concrete) in my house. No way I can replace it. But it's 20-25 meters max. Looks like I can use 10 Gbps in the future, without pulling new cables. Nice.
 

mikegg

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Jan 30, 2010
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Gryz, thanks that's what I'm looking for but I'm wondering if anyone has any reliable tests that show cat5e doing 10gbps at 45 meters.

I too, have cat5e in my house that I can't replace. I'm thinking about ordering Comcast's 2 Gigabit Fiber service which is obviously more than what cat5e is rated for.
 

Gryz

Golden Member
Aug 28, 2010
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You could ask Comcast.

If they sell 2Gbps service, they must have many other customers with exactly the same problem. If you have 2 Gbps Internet, you have no other choice but to get 10 Gbps equipment in your home-network. I wonder what kind of router they supply, or recommend. It must be a router with a 10 Gbps interface.

There must be many more people with the exact same problem. Comcast might have good advice for customers like you.
 

Pheran

Diamond Member
Apr 26, 2001
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There must be many more people with the exact same problem. Comcast might have good advice for customers like you.

Or, more likely, the Comcast rep won't have the faintest idea what they are talking about. I've dealt with enough ISPs to be cynical about this. But, they do have this web page:

http://customer.xfinity.com/help-an...ts-to-run-xfinity-internet-speeds-over-1-gbps

So yeah, the bottom line is that you need 10Gbps equipment if you actually want the 2Gbps speed, which is going to cost a pretty penny.