Your Ethernet is slow because of cables, not the switch

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lchiu7

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#323552 14-Dec-2025 15:55

Recently came across this article about why your Internet is slow even thought you have gigabit Internet

https://www.xda-developers.com/slow-ethernet-cables-fault-not-switch/

it's not entirely clear the situation described but they seem to say you need Cat5E or Cat6 to get the faster speed. I am not sure that is the case.

A while ago when I first got gigabit fibre I could not work out why I was only getting about 200Mbs transfer rate. Some sage people on GZ advised me to look at the patch cables I was using to connect my devices to the switch and check to see if they had five or six cables wires. Apparently some cheap cables from router suppliers only had 5 cables patched since they didn't really expect people to be doing gigabit on the network (back then). Sure enough a quick cheap on one of my patch cables showed only 5 lines connected and switching to one that had 6 restored my speed.

I wonder if patch cables that are Cat 5 versus 6 would really make that much difference in a home work, especially when you are just connecting to your router?

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Jase2985

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#3443957 14-Dec-2025 16:33

Given the fact CAT5 and CAT6 have no relations to the number of cables connected and that even with 6 cables connected you still wouldn't get faster speeds, I would say you don't understand the technology and have attributed it working by just blindly changing something.

4 wires, 2 pairs, gives you a 100Mbps connection, 8 wires, 4 twisted pairs give you 1000Mbps (1Gbps) or 10Gbps depending on the distance.

Cat5 cable will do 1Gbps to about 30M, Cat5e to about 100m and might even do 10Gbps to short distances. Cat6/6a will to 10Gbps at distances over 30m, CAT7 and 8 are just more highly shielded versions of CAT6

it's recommend to use CAT5e or higher between your router and switches due to better interference suppression. It shouldn't make any difference in the speeds you see, as both are rated to 1Gbps

lchiu7

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#3443958 14-Dec-2025 16:48

I understand why 4 pairs gives you gigabit and 2 pairs slower. The point I was making was, the article seems to imply moving from Cat 5 to Cat 6 will produce a measurable speed increase and I am not sure that is the case in the author's situation.

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Bung

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#3443960 14-Dec-2025 17:24

The author was a mechanical design engineer turned tech reporter and reviewer. That type of article often has more value in the comments following.

SirHumphreyAppleby

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#3443962 14-Dec-2025 17:34

The article has no redeeming qualities and should be ignored.

Who was using Cat5 a decade ago? The Cat5e and Cat6 specs are both more than two decades old. I suppose in the early days (after switching from 10base2) I may have used some Cat5 cables, but I don't recall ever using anything other than Cat5e or Cat6[A].

Cat5e/Cat6 isn't going to make any difference in performance. A bad cable is a bad cable regardless of the standard used, and if undamaged, their age is irrelevant.

Jase2985

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#3443963 14-Dec-2025 18:50

lchiu7:

I understand why 4 pairs gives you gigabit and 2 pairs slower. The point I was making was, the article seems to imply moving from Cat 5 to Cat 6 will produce a measurable speed increase and I am not sure that is the case in the author's situation.

but you didnt say that in your post... you said 5 wire vs 6.

Unless you are an edge case, cat5e vs cat6, it's likely not the answer. Though, there are some cables that are made better than others.

lchiu7

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#3444011 14-Dec-2025 20:23

I probably wasn't clear. I said in the end

I wonder if patch cables that are Cat 5 versus 6 would really make that much difference in a home work, especially when you are just connecting to your router?

My point was the difference in speed I experienced was due to the number of pairs connected and I wondered (clearly not clear enough :-( ) is that what the author was experiencing?

I should have read all the comments on the post which basically make similar points.

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Tinkerisk

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#3444044 15-Dec-2025 00:42

lchiu7:

I understand why 4 pairs gives you gigabit and 2 pairs slower. The point I was making was, the article seems to imply moving from Cat 5 to Cat 6 will produce a measurable speed increase and I am not sure that is the case in the author's situation.

Sometimes, it is. For 10Gb/s. 😁

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richms

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#3444111 15-Dec-2025 10:21

I have one run of cat5 in the house that will not work with some devices at 10 gig, and for others is random if it gets 5 gig or 10 gig link over it (assuming the other device supports 5) - its the longest one that goes all the way up to the roof space, along the whole length of the house and down at the other end, and then down to the floor below it. Cable was pulled that way as it was done at the same time as others, its a stupid way to run it and I think it may have a bit of damage too where it was pulled thru by an old phone cable that went upstairs from downstairs.

Everything else is fine with 10 gig, and shows no significant port error counts. I can't see what that run does for errors because my unifi switches with cheap SPF+ modules are what will not do 10 over it.

Richard rich.ms

Tinkerisk

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#3444305 15-Dec-2025 18:02

richms:

Everything else is fine with 10 gig, and shows no significant port error counts. I can't see what that run does for errors because my unifi switches with cheap SPF+ modules are what will not do 10 over it.

For longer distances and in general (where possible), I use optical 10Gb/s SFP+ modules, as these connections consume much less power than 10Gb/s Ethernet cables. For short distances, I use DAC cables. Some servers only have 10Gb/s Ethernet, but I convert this straight away using a converter module on the 10G SFP+ switch.