Cat 5e cable 10MBps instead of 1Gbps

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d5775927

Getting comfortable
Dec 11, 2019
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Israel
I bought this cable:
Used it to connect two computers, used about 20 meters (65ft), i'm only getting 10 Mbps instead of 1Gbps.
Tested the following:
1. Visually inspected the cable ends (to see all wires are crimped)
2. Used a tool to make sure the order is correct (tool with 8 lights, 1 light per wire ...)
3. Tried to crimp one of the ends again
4. Tried to connect two computers instead of router to computer
In all cases the link only works on 10 Mbps rate.

Along the way, the Cat5e cable is close to electricity cables (on the attic), may this be the reason?

I've used the same cable to wire two Dahua cameras to a Dahua NVR and I didn't have any issues.
 
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do you mean that your interfaces are auto negotiating to 10Mbps or do you mean you are testing the connection and maxing out at 10Mbps transfer rate?

Try manually setting the interfaces to 1Gb
for throughput testing, try iperf

edit - also, try with a known good cable and compare results.
 
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d5775927 said:
4. Tried to connect two computers instead of router to computer
Click to expand...
So the NIC's of both PC's and/or the switch portion of the router are ALL said to be gigabit rated?
 
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Sphinxicus said:
do you mean that your interfaces are auto negotiating to 10Mbps or do you mean you are testing the connection and maxing out at 10Mbps transfer rate?

Try manually setting the interfaces to 1Gb
for throughput testing, try iperf

edit - also, try with a known good cable and compare results.
Click to expand...
The NIC config show 10 Mbps, so no need to try iperf (tried spped test got 10 Mbps).
Other cables work well.
 
d5775927 said:
Other cables work well.
Click to expand...
That would have been good to know early on, I guess. :cool:
d5775927 said:
Along the way, the Cat5e cable is close to electricity cables (on the attic), may this be the reason?
Click to expand...
If all else fails, I'd try to maintain at least 3 ft spacing if parallel and if crossing is required try to do so at a right angle.
 
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You've probably got a real problem with the connectors/crimps. I have some CAT5 patch cables, only 15 feet but CAT5, that run at 1GB with no problem on auto-negotiated ports of PCs, switches and routers.
 
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I agree, try new RJ45 connectors on both ends. When I was new to ethernet cable crimping I messed them up all the time with wires being too short or not penetrated properly. Not all RJ45 connectors are equal, and some might be just poor quality or a bad match for your cable. If the problem persists then it is probably either a bad section of the cable or interference from your electric power wires.

If you think it is the interference causing the problem and you can't avoid it, you can consider replacing the run with fiber optics. It would cost about $80 and it is just plug-and-play with this pair of media converters and this long fiber patch cable. Any length of cable will work, just make sure it is multi mode (OM1, OM2, OM3, OM4, or OM5 spec) with "LC" connectors in order to match the transceivers that come with the media converters I linked. Learn more about fiber optic networking here.
 
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d5775927 said:
I bought this cable:
Used it to connect two computers, used about 20 meters (65ft), i'm only getting 10 Mbps instead of 1Gbps.
Tested the following:
1. Visually inspected the cable ends (to see all wires are crimped)
2. Used a tool to make sure the order is correct (tool with 8 lights, 1 light per wire ...)
3. Tried to crimp one of the ends again
4. Tried to connect two computers instead of router to computer
In all cases the link only works on 10 Mbps rate.

Along the way, the Cat5e cable is close to electricity cables (on the attic), may this be the reason?

I've used the same cable to wire two Dahua cameras to a Dahua NVR and I didn't have any issues.
Click to expand...

Q: Along the way, the Cat5e cable is close to electricity cables (on the attic), may this be the reason?

Answer: Yes.

parallel runs are especially prone to issues .. in general I try to keep my cat5e/6 runs away from electrical lines, ballasts, motors .. inverse R squared rule applies .. 2x the distance from the electrical line, gives you 1/4 the interference ..

In practice, I try to keep at least 1 foot away from electrical lines .. ( I have not measured the results, and in cases where you have to go closer I have used a section of EMT conduit to shield the cat5e/6 runs .. )
 
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TechieTech said:
Do both computers have 1GB NIC cards and are they set to auto negotiate the connection speed? If so, try setting or both of them to 1GB manually.
Click to expand...
Asked in post #4, answered in 5 & 7..... :cool:
 
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With a short run like this, I can't imagine that electrical wires would drop the speeds this significantly unless a huge portion of the run follows the electrical wires. I would think that it's more likely that the wire is damaged in some way. Maybe there's a nail in the attic that ripped it up. Or maybe it got kinked while being pulled around a corner.

I would also recrimp both ends to make absolute sure that they are crimped correctly
 
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Ok my take on the situation, I’ve had a similar experience when I wired up my sons room with a pair of cat5e cables around 20m in length, any device connected to either would blip 1Gb then drop down to 100Mb and what I found was that my 3com 8 port switch just couldn’t properly drive the cable and maintain a reliable 1Gb connection so it would drop.

In the end I replaced the switch with a Dell 16 port device which I just happened to have and both pairs now reliably maintain 1Gb.

It’s not clear how you have the devices connected ie direct via a x-over cable or via a switch but hopefully the above might give you something to test?
 
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