Question Why are my speeds capped at 100Mbps when going through wired ethernet in house ?

[sam2k51]

Hello,

I've recently moved into a new house (built in 2018) which has built in ethernet ports throughout the house. They were annoying not labelled but I've now figured out what port near my router relates to what port in other rooms.

I've recently tried plugging my game console in through the port in the lounge and then from the related port by my router and then into the router. I should be getting speeds of around 500Mbps (and I do get this when I test via WiFi) but the console only gets 100.

I've tested quite a few things, like plugging directly into the router and my speeds go up to 500, tested both cables also checked the ports themselves and they are both wired up as T568B and also checked all of the other ports in the house and they are only getting 100Mbps as well and I can't figure out why I'm getting a low speed.

Does anyone have any ideas what's causing it to be slow? Also please bear with me I'm new to a lot of this and I'm still learning!

 

[kanewolf]

Hello,

I've recently moved into a new house (built in 2018) which has built in ethernet ports throughout the house. They were annoying not labelled but I've now figured out what port near my router relates to what port in other rooms.

I've recently tried plugging my game console in through the port in the lounge and then from the related port by my router and then into the router. I should be getting speeds of around 500Mbps (and I do get this when I test via WiFi) but the console only gets 100.

I've tested quite a few things, like plugging directly into the router and my speeds go up to 500, tested both cables also checked the ports themselves and they are both wired up as T568B and also checked all of the other ports in the house and they are only getting 100Mbps as well and I can't figure out why I'm getting a low speed.

Does anyone have any ideas what's causing it to be slow? Also please bear with me I'm new to a lot of this and I'm still learning!

There are a few possible reasons. But bad terminations on the in-wall wiring is #1. Then the obvious error of using an old 100Mbit ethernet switch rather than a gigabit. Third possibility is you have a laptop which only has 100Mbit hardware. Fourth you have damage to one of the eight wires in your ethernet port.

 

[USAFRet]

Capped at ~100mbps is almost certainly cable related.

 

[chillhouse1]

try uncap ethernet speed, open device manager, then properties-advanced of network adapter, then select Speed and Duplex from the Property column, and expand the Value dropdown

 

[sam2k51]

There are a few possible reasons. But bad terminations on the in-wall wiring is #1. Then the obvious error of using an old 100Mbit ethernet switch rather than a gigabit. Third possibility is you have a laptop which only has 100Mbit hardware. Fourth you have damage to one of the eight wires in your ethernet port.

Thank you for the help! Do you think it would be worth rewiring 2 of the ports to see if that makes a difference?

Also I'm not sure if there is a switch or if it is just straight A to B, I've had a look around my house by I can find any sort of switch anywhere, is there any way to find out?

I don't think it is the laptop as I have used it wired before in other places and got much faster speeds!

 

[dev_cyberpunk]

Does anyone have any ideas what's causing it to be slow? Also please bear with me I'm new to a lot of this and I'm still learning!

bad cabling or router.
disconnect all of the lan ports but 1 and go to that end and speed test it. Also, find out what connection link speed its running by looking at the status of the ethernet interface in the network properties window.

If you have a damaged and shorted cable, the instant you plug it in, the problem will return.

Otherwise there are other things that can be wrong. like too long of runs, kinks in the wire, or they used the wrong type and the heat deteriorated the cables.

 

[LordVile]

bad cabling or router.
disconnect all of the lan ports but 1 and go to that end and speed test it. Also, find out what connection link speed its running by looking at the status of the ethernet interface in the network properties window.

If you have a damaged and shorted cable, the instant you plug it in, the problem will return.

Otherwise there are other things that can be wrong. like too long of runs, kinks in the wire, or they used the wrong type and the heat deteriorated the cables.

Just sounds like they used Cat5 cable

 

[dev_cyberpunk]

Just sounds like they used Cat5 cable

plenum grade in residential walls and attic degrade, plus if runs have twists and kinks in the wire its done. The speeds they reported seemed to come from an internet speed test than the actual link speed.
I installed my own networks, one 10Gb and 1Gb about 15 years ago. Both were cat 6 CMX wire and never had issues. Since CAT 8 CMX bulk is cheaper now, I'm going to be adding that and use the spare cat 6 for distributed audio.

 

[LordVile]

plenum grade in residential walls and attic degrade, plus if runs have twists and kinks in the wire its done. The speeds they reported seemed to come from an internet speed test than the actual link speed.
I installed my own networks, one 10Gb and 1Gb about 15 years ago. Both were cat 6 CMX wire and never had issues. Since CAT 8 CMX bulk is cheaper now, I'm going to be adding that and use the spare cat 6 for distributed audio.

Generally if it degrades tough you'll have more issues than just a drop in speed and being limited to exactly the Cat5 cap is a little too neat for me.

 

[sam2k51]

Just sounds like they used Cat5 cable

It looks like they used Cat5e, at least that's what the ports say (I suppose they could've have used Cat5 cable still though).

plenum grade in residential walls and attic degrade, plus if runs have twists and kinks in the wire its done. The speeds they reported seemed to come from an internet speed test than the actual link speed.
I installed my own networks, one 10Gb and 1Gb about 15 years ago. Both were cat 6 CMX wire and never had issues. Since CAT 8 CMX bulk is cheaper now, I'm going to be adding that and use the spare cat 6 for distributed audio.

I'm getting the speeds from speed tests and also my router shows me what the max speed is for each cable device when plugged in. Anything going through the ports in the wall say max 100Mbps. (When plugging directly into the router it goes up to 1Gb)

 

[sam2k51]

Generally if it degrades tough you'll have more issues than just a drop in speed and being limited to exactly the Cat5 cap is a little too neat for me.

I have asked around a couple of places and people seem to think that there might be a hidden switch or panel, but looking around the house I can't seem to find anything!

 

[bill001g]

I like this device because it will let you locate wires as well as test ethernet wiring. There are many other units I just happen to have a link to this one.

https://www.amazon.com/dp/B07TMDFG3W

These cheap unit though will not find stuff like if you have the wrong color wires on the wrong pins. The that units can detect when the pairs are split and stuff are extremely expensive.

You are best off looking at the wiring and see if it follows pattern 568a or 568b.

Ethernet cables are point to point. If there is a switch the cables likely go to some central location. You can run a device like this to first find both ends of cable. You plug the sender into some jack and then take the probe and listen for a tone when you touch other cables. This unit is not good enough to trace wires in the walls but for more money those devices do exist.

After you find both ends and you think the wires colors and pattern look correct you can test if the port really works and all 8 pins can send signals end to end.

In general when a port runs at only 100mbps there is a issue with either the blue or brown pair...assuming 568a/b wiring patterns. You used to see ports wired with only 4 wires rather than all 8 that also causes it to only run at 100mbps.

 

[sam2k51]

I like this device because it will let you locate wires as well as test ethernet wiring. There are many other units I just happen to have a link to this one.

https://www.amazon.com/dp/B07TMDFG3W

These cheap unit though will not find stuff like if you have the wrong color wires on the wrong pins. The that units can detect when the pairs are split and stuff are extremely expensive.

You are best off looking at the wiring and see if it follows pattern 568a or 568b.

Ethernet cables are point to point. If there is a switch the cables likely go to some central location. You can run a device like this to first find both ends of cable. You plug the sender into some jack and then take the probe and listen for a tone when you touch other cables. This unit is not good enough to trace wires in the walls but for more money those devices do exist.

After you find both ends and you think the wires colors and pattern look correct you can test if the port really works and all 8 pins can send signals end to end.

In general when a port runs at only 100mbps there is a issue with either the blue or brown pair...assuming 568a/b wiring patterns. You used to see ports wired with only 4 wires rather than all 8 that also causes it to only run at 100mbps.

Thanks for the advice, I've got a very basic cable tester and have found which ports connect to which but not sure what else it can help with https://amzn.eu/d/jiFJ0TKi

I've checked the wiring and while its not the nearest it seems to be 568B on both ends. Sorry not sure how to post photos!

 

[dev_cyberpunk]

It looks like they used Cat5e, at least that's what the ports say (I suppose they could've have used Cat5 cable still though).

yes, open up a wall jack and observe what wire they used (printed on the cable) as well as to check if they didn't do something dumb like cram the wires into the wall.

 

[dev_cyberpunk]

I have asked around a couple of places and people seem to think that there might be a hidden switch or panel, but looking around the house I can't seem to find anything!

Do you have more Ethernet outlets than the router?

If so, the two places I normally find switches in bad installs I used to redo is in in closets and in the attic. The other somewhat bad place was in the garage. But if you have a switch in these areas, you have to buy special switches that can handle extreme temperatures if you don't plan to rewire.

 

[dev_cyberpunk]

Generally if it degrades tough you'll have more issues than just a drop in speed and being limited to exactly the Cat5 cap is a little too neat for me.

What usually happens is just one wire fails, which could be it if the problem goes away when all but one good run is connected to the router. But it does act like someone has put a regular switch in the attic since they can't find it, but they haven't answered the question yet if there is more ethernet outlets than the router has.

 

[sam2k51]

What usually happens is just one wire fails, which could be it if the problem goes away when all but one good run is connected to the router. But it does act like someone has put a regular switch in the attic since they can't find it, but they haven't answered the question yet if there is more ethernet outlets than the router has.

So I've checked and it is definitely using Cat5e cable, I can see it near the ports next to the router.
And in terms of ports there are 4 at the router and then 4 in other rooms of the house so I presumed it was just A to B but I can't figure out why the speeds are so slow so leaning towards there being a panel/switch. Annoyingly if it's in the attic I don't currently have a ladder! It's the only place I haven't checked

 

[dev_cyberpunk]

So I've checked and it is definitely using Cat5e cable, I can see it near the ports next to the router.
And in terms of ports there are 4 at the router and then 4 in other rooms of the house so I presumed it was just A to B but I can't figure out why the speeds are so slow so leaning towards there being a panel/switch. Annoyingly if it's in the attic I don't currently have a ladder! It's the only place I haven't checked

well its probably doesn't have a switch, and its most likely either bad installation run (kinks in the wire) or they used CM, CMP or CMG cable as these types should never be used in attic + wall runs.

Other things come into mind too like the house might of had a mouse infestation and they chewed the wires, or the router needs to be replace because its loosing signal drive.

 

[bill001g]

If it is multiple ports then it is more likely someone wired them wrong. A single port can be some wire manged to get loose over time. Most times in wall wires never fail. Maybe if you plug thing in and out of jack too many times they might wear out but they tend to take a lot of abuse and still work.

So maybe I missed it. DId you ever post the router model. It is not real important to post it but be very sure the ports on the router are gigabit. Routers with 100mbps lan ports are actually fairly rare but if the router is older it used to be very common.

If the ports are gigabit then we are back to cabling.

Very technically the colors of the wires don't matter but the pattern of which pins are connected in which pair matters a lot. Using non standard colors works but make life very confusing for the next guy.

Check very carefully that the wires follow one of the 2 common color patterns. What confuses people is the pairs go 1,2. 3,6. 4,5. 7,8. All the other pairs are on pins next to each other except the pair that is on 3,6. You see people wire 1,2 3,4 5,6 7,8. This tends to not work at all but it might work at 100mbps.

 

[sam2k51]

If it is multiple ports then it is more likely someone wired them wrong. A single port can be some wire manged to get loose over time. Most times in wall wires never fail. Maybe if you plug thing in and out of jack too many times they might wear out but they tend to take a lot of abuse and still work.

So maybe I missed it. DId you ever post the router model. It is not real important to post it but be very sure the ports on the router are gigabit. Routers with 100mbps lan ports are actually fairly rare but if the router is older it used to be very common.

If the ports are gigabit then we are back to cabling.

Very technically the colors of the wires don't matter but the pattern of which pins are connected in which pair matters a lot. Using non standard colors works but make life very confusing for the next guy.

Check very carefully that the wires follow one of the 2 common color patterns. What confuses people is the pairs go 1,2. 3,6. 4,5. 7,8. All the other pairs are on pins next to each other except the pair that is on 3,6. You see people wire 1,2 3,4 5,6 7,8. This tends to not work at all but it might work at 100mbps.

I've got a new Amazon eero 6+, it only has one LAN port and it supports 1Gbps and can confirm I get good speeds when plugged directly into it. It's only when going through the ports in the wall that it gets limited to 100Mbps.

Looking at the ports they are wired as shown on the port itself, here's a link to a twitter post I made with photos, they aren't the neatest but it seems like they are put in the right places.

https://twitter.com/x/status/1894091587006709929

View: https://x.com/Sam_Felts/status/1894091587006709929?t=9aqzx9Yc429GAxYvdCjiiA&s=19

 

[dev_cyberpunk]

I've got a new Amazon eero 6+, it only has one LAN port and it supports 1Gbps and can confirm I get good speeds when plugged directly into it. It's only when going through the ports in the wall that it gets limited to 100Mbps.

Looking at the ports they are wired as shown on the port itself, here's a link to a twitter post I made with photos, they aren't the neatest but it seems like they are put in the right places.

https://twitter.com/x/status/1894091587006709929

View: https://x.com/Sam_Felts/status/1894091587006709929?t=9aqzx9Yc429GAxYvdCjiiA&s=19

punch downs are installed incorrectly.

They should look like this (sorry for the blurry of the old phone camera)

 

[kanewolf]

I have asked around a couple of places and people seem to think that there might be a hidden switch or panel, but looking around the house I can't seem to find anything!

Have you tried bypassing all cabling and directly connecting the device to your primary router? That could be a long cable you lay across the floor or by moving your device close to your primary router.

 

[sam2k51]

punch downs are installed incorrectly.

They should look like this (sorry for the blurry of the old phone camera)

Oh okay I wasn't sure, quite new to all of this! How easy it is to rewire? And can I reuse the same port?

 

[kanewolf]

Oh okay I wasn't sure, quite new to all of this! How easy it is to rewire? And can I reuse the same port?

Maybe. BUT, since you don't know for SURE that the keystone doesn't have an internal problem, I would recommend buying new ones.

 

[sam2k51]

Maybe. BUT, since you don't know for SURE that the keystone doesn't have an internal problem, I would recommend buying new ones.

Good point, do you know where is best to buy things like that (UK)? Looked on Amazon but looks like they only sell the whole plate rather than the ports.