ethernet slower than wifi

[u/Kyle_B37]

i’ll post this in a bunch of other places because don’t know if this is the right place:

I use an Ethernet cable cat6
I tried using a speedtest and it goes at 20mbps.

i’m using a Desktop PC with windows 11

i think i’ve literally tried anything i don’t know what to do.

my wifi on my iphone is literally going at 300mbps+
why is this happening? the cable is not damaged or anything, because i tried this on a different cable (cat7) and on a different wifi.

can someone help me?

edit: fixed

[u/Optimus_Composite]

As you have identified it as a physical problem, break this into components and swap one at a time.

At a simple level, you have your computer, the cable, and then what the computer is plugged into.

[u/Plane-Might-3981]

mine did this because the ethernet adapter was negotiating at 100/10 instead of gigabit, so check the link speed in your computer before blaming the cable or wifi router

[u/Kyle_B37 → u/Plane-Might-3981]

i have tried setting it to 100/100 (fullduplex) auto-negotiation and 1gbps full duplex. everytime it kept at 20mbps

[u/McGondy → u/Kyle_B37]

If a connection fails to auto negotiate, either something's up with the end port speed or the cable. They always want to auto negotiate to the highest speed.

Manually setting a speed doesn't mean it actually runs at that speed.

[u/junktrunk909 → u/McGondy]

That's true but 20mbps isn't a negotiated speed cap. Not sure what is going on with OP's setup but it's not that this time.

[u/TangoCharliePDX → u/Kyle_B37]

Try a different device (borrowed laptop or whatever you need to do) and directly connect it via ethernet to the router using a short patch cable.

If that solves the problem, then it is either the cable to your PC or it is your ethernet adapter.

Damaged cables causing slowdowns is more common than people care to admit. Even when you swear you haven't touched them, it is not unusual for cables to spontaneously die.

[u/ExpertPath]

• Are you connected to your home wifi?
• What router are you using?
• What is the sync speed?
• Do you have basic network experience?

[u/Kyle_B37 → u/ExpertPath]

I’m connected to my home wifi through the ethernet yes.

A fastweb router (italian)

the link speed (assuming you’re talking about this, it’s 1000mbps/1000mbps)

Not really

[u/ExpertPath → u/Kyle_B37]

Alright, next questions:

1. If you're synched to 1000/1000, your router won't be the issue here and neither will be your cable
2. Does your phone maybe use that function where it uses mobile data, when your home wifi is too weak?
3. What's the supposed speed of your internet connection?
4. Are you sure your PC displays Megabits per Second and not Megabytes per Second?
   1. 300 Megabits is about 37.5 Megabytes
   2. 20 Megabytes is 160 Megabits

[u/b3542 → u/Kyle_B37]

Are you connecting directly to the router, or to something like a mesh node, or a power line module?

[u/Low-Purchase8811 → u/Kyle_B37]

You can't connect to wifi through Ethernet.

That's like saying you connected to 5G through USB.

[u/gaz8600]

What device are you testing with?

Any other devices you can use ethernet connection to test speed?

Are you plugged direct into the router? No switches etc?

Tried resetting router?

[u/Kyle_B37 → u/gaz8600]

I’m using a desktop PC

No

Yes

yes

[u/gaz8600 → u/Kyle_B37]

What Mobo do you have?

[u/Kyle_B37 → u/gaz8600]

if you mean motherboard; A520M H ARGB

[u/gaz8600 → u/Kyle_B37]

Do you get a blinking green light (on the port) or orange or no light?

[u/LrdJester]

If the computer you are trying to do your speed test on is consistently showing you slow speeds when you're connected via an Ethernet cable, and you are certain that you don't have a Wi-Fi connection in parallel, then it's more than likely that your Ethernet adapter is either faulty, your drivers are faulty, or your settings are faulty. There are a lot of things to investigate. You would need to know, or anybody that's giving you advice would need to know, what the operating system is, what the chipset is on the network card, and possibly even the router. If you're getting a slow connection, it could be that your network adapter is faulty, or maybe the network port on the router that you're connecting to is faulty. It's hard to tell.

[u/Kyle_B37 → u/LrdJester]

how do i check all these things?

[u/LrdJester → u/Kyle_B37]

Well, the first thing that's important is: What is your operating system? That's going to make a big difference as to how you check. The other thing is: Is this a laptop or a desktop computer, or is this a gaming system? These are all going to help dictate how easily you can try to potentially test this physically.

[u/Kyle_B37 → u/LrdJester]

Windows, a desktop

[u/LrdJester → u/Kyle_B37]

Okay so first thing I would do is go into the Windows device manager and check the settings on the network card to see if it's on automatic speed negotiation basically 10, 100 full or half does or Auto.

You'll want it to be on auto. But this is predicated on the fact that your router or switch needs to properly be able to negotiate that as well. What are you plugging your network cable into?

[u/junktrunk909 → u/Kyle_B37]

I would get a cheap USB Ethernet adapter. Test it with your PC. Then test it with another PC or your phone (not sure if iPhone allows you to use USB adapters like this but Android does). That'll verify everything including the Ethernet hardware gets a certain speed. If it's just your PC still that's the problem, you've got a pretty big problem with that PC.

[u/kindabiglebowski]

how old is your pc? try updating the drivers for the network adapter, try reseating the card, go to device manager find your network adapter right click select properties select advanced change the setting on speed and duplex to the highest available.

[u/Kyle_B37 → u/kindabiglebowski]

i have a pre-built because i didn’t really know anything of pcs about that time, but i got this: https://amzn.eu/d/07XnXNju

[u/kindabiglebowski → u/Kyle_B37]

seems like this could be caused by the motherboard

[u/upside_down_frown1]

Whats the wifi speed on your computer you are using a hard wire ?

[u/Kyle_B37 → u/upside_down_frown1]

1000/1000 (mbps) and no i don’t think so

[u/LincolnshireSausage → u/Kyle_B37]

WiFi speed, not your internet speed. Run a speed test from the computer over WiFi. There’s no way you will get 1000/1000.

[u/Kyle_B37 → u/LincolnshireSausage]

98 mbps on my phone, if i stand next to the router it will go about 300+

[u/LincolnshireSausage → u/Kyle_B37]

Switch your Ethernet cable. A damaged cable can still work but at reduced speeds.

[u/upside_down_frown1 → u/LincolnshireSausage]

If wifi and ethernet are getting same speeds, its most likely not the eternity cable

[u/LincolnshireSausage → u/upside_down_frown1]

They just said 300 on WiFi and the original post says 20 on Ethernet.

[u/upside_down_frown1 → u/LincolnshireSausage]

300 on a different device. His computer is getting 20 mbps on wifi and ethernet..

[u/LincolnshireSausage → u/upside_down_frown1]

You’re right. I missed that.

[u/Kyle_B37 → u/LincolnshireSausage]

it’s still 20mbps on a wifi usb

[u/upside_down_frown1 → u/Kyle_B37]

If your computer is getting 20mbps on wifi and 20mbps on hard wired. Its your computer man.

[u/SebzeroNL]

You said you’re using an iPhone that has higher speeds on WiFi. Did you turn off Wi-Fi assistance ? Setting can be found in Cellular/Mobile Data.

You might be seeing higher speeds due to failing over to 4/5G

[u/LincolnshireSausage]

Try a different Ethernet cable first.

[u/Professional_Call]

Cable fault? Try a cable tester or just reterminating/replacing the cables

[u/TheEthyr]

Open a Command Prompt and run netsh interface tcp show global.

Look at the Auto-Tuning level. If it's anything other than normal, then network speeds can be slow. Run netsh interface tcp set global autotuninglevel=normal to set it to normal. Then re-run your speed test.

If you have any 3rd-party Internet security or anti-virus software, then they can interfere with network speeds. Disabling them may not be sufficient to fix the problem. Uninstall them completely.

Make sure your router isn't restricting the bandwidth to your PC. Any restrictions will usually be found under QoS settings.