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Why do I have slow internet?

Why do I have slow internet?

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Brandon_En
Member
246
04-15-2026, 06:32 PM
#1
Hey, I'm having a computer issue where my internet speed is stuck at 100 megabits per second. It used to work better before, and that happened after I reinstalled Windows and updated the network driver on my LAN card. I tried using the same cable with another computer that gets the right speed instead, and even forced my settings to Gbps without fixing anything. I have no idea what's going wrong because the cable is working fine, but something strange is happening inside my PC. Can anyone help me figure out why?
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Brandon_En
04-15-2026, 06:32 PM #1

Hey, I'm having a computer issue where my internet speed is stuck at 100 megabits per second. It used to work better before, and that happened after I reinstalled Windows and updated the network driver on my LAN card. I tried using the same cable with another computer that gets the right speed instead, and even forced my settings to Gbps without fixing anything. I have no idea what's going wrong because the cable is working fine, but something strange is happening inside my PC. Can anyone help me figure out why?

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SlasherG
Member
54
04-15-2026, 07:20 PM
#2
It is usually a bad cable. If your PC runs on auto, changing the setting might confuse the router or switch because there isn't really another option to set other than auto. You probably think your cable works fine if it worked on another device. But this other device can handle a slightly weak cable better than your PC does. The speed settings are checked by hardware and not software, so even if you don't have a bad cable, maybe there is a broken port inside the PC that isn't showing up. You'd need an extra card to fix that. Finding a bad port in a machine is very rare. It usually doesn't make sense to try to fix a cable unless it's really long or hard to replace because you might have to dig through walls. Your best choice will probably be just buying a new cable. There are lots of fake cables out there, and if yours isn't actually an ethernet cable, that could be the problem too. You want real copper wires without the extra CCA layer and the right wire size (22 or 24). Cat5e can do gigabit speeds easily, but you don't need any better speed with cat6 either.
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SlasherG
04-15-2026, 07:20 PM #2

It is usually a bad cable. If your PC runs on auto, changing the setting might confuse the router or switch because there isn't really another option to set other than auto. You probably think your cable works fine if it worked on another device. But this other device can handle a slightly weak cable better than your PC does. The speed settings are checked by hardware and not software, so even if you don't have a bad cable, maybe there is a broken port inside the PC that isn't showing up. You'd need an extra card to fix that. Finding a bad port in a machine is very rare. It usually doesn't make sense to try to fix a cable unless it's really long or hard to replace because you might have to dig through walls. Your best choice will probably be just buying a new cable. There are lots of fake cables out there, and if yours isn't actually an ethernet cable, that could be the problem too. You want real copper wires without the extra CCA layer and the right wire size (22 or 24). Cat5e can do gigabit speeds easily, but you don't need any better speed with cat6 either.

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EvilOpero
Junior Member
3
04-21-2026, 07:16 AM
#3
I put it back to auto mode, tried a new cable too, but nothing changed. The laptop is getting the same speed as my internet connection gives me, but my computer keeps stuck at 100Mbps. In the picture, the laptop is on one side and my big monitor is on the other.
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EvilOpero
04-21-2026, 07:16 AM #3

I put it back to auto mode, tried a new cable too, but nothing changed. The laptop is getting the same speed as my internet connection gives me, but my computer keeps stuck at 100Mbps. In the picture, the laptop is on one side and my big monitor is on the other.

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BionicTaco420
Member
163
04-27-2026, 12:30 AM
#4
So, double check that your settings are set to "auto". Try changing the port number in your router. .....Note: I will assume this cable goes directly from your PC to the modem and doesn't connect through any extra wall jacks. After this step, you'll have very few options left to try. You could buy a new PCIe or USB3 ethernet card. They aren't expensive, but it is probably cheaper just to get a brand-new Ethernet cable so you are 100% sure before buying a new port. It is really hard to break an old port unless someone physically cracks it open.
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BionicTaco420
04-27-2026, 12:30 AM #4

So, double check that your settings are set to "auto". Try changing the port number in your router. .....Note: I will assume this cable goes directly from your PC to the modem and doesn't connect through any extra wall jacks. After this step, you'll have very few options left to try. You could buy a new PCIe or USB3 ethernet card. They aren't expensive, but it is probably cheaper just to get a brand-new Ethernet cable so you are 100% sure before buying a new port. It is really hard to break an old port unless someone physically cracks it open.

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69
05-04-2026, 09:28 AM
#5
It is a straight wire from my router to my computer. Even if I switch ports on the router, nothing changes and the problem stays the same. So it must be the port on my PC. That feels strange though. I just recently flashed my BIOS so I could change my CPU, then I also reset Windows. I can't figure out how that would mess up my connection.
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Dimond_miner27
05-04-2026, 09:28 AM #5

It is a straight wire from my router to my computer. Even if I switch ports on the router, nothing changes and the problem stays the same. So it must be the port on my PC. That feels strange though. I just recently flashed my BIOS so I could change my CPU, then I also reset Windows. I can't figure out how that would mess up my connection.

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earterms123
Junior Member
8
05-04-2026, 11:19 AM
#6
You might check your BIOS settings to see if anything changed. Those green power saver options can sometimes cause trouble, but mostly they just don't work well with long cables. It's probably not about the drivers either; for instance, if you didn't load the chipset drivers when you installed them, your ethernet port wouldn't show up at all. Usually, this problem is caused by a cable instead.
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earterms123
05-04-2026, 11:19 AM #6

You might check your BIOS settings to see if anything changed. Those green power saver options can sometimes cause trouble, but mostly they just don't work well with long cables. It's probably not about the drivers either; for instance, if you didn't load the chipset drivers when you installed them, your ethernet port wouldn't show up at all. Usually, this problem is caused by a cable instead.

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AzuzzSaphixx
Member
55
05-04-2026, 12:18 PM
#7
I honestly have no idea why those strange settings are acting up. I even tried swapping out my PC's cables and it didn't change anything either. So, I'm pretty sure the problem lies with the port on my motherboard.
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AzuzzSaphixx
05-04-2026, 12:18 PM #7

I honestly have no idea why those strange settings are acting up. I even tried swapping out my PC's cables and it didn't change anything either. So, I'm pretty sure the problem lies with the port on my motherboard.

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IceFlame56YT
Member
73
05-05-2026, 07:46 AM
#8
Were you going faster on your PC before? Do you have a specific motherboard or is it a prebuilt thing? If you got the same speed back then, I think it might be because of drivers or settings. Has anything in Device Manager had an exclamation mark next to it?
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IceFlame56YT
05-05-2026, 07:46 AM #8

Were you going faster on your PC before? Do you have a specific motherboard or is it a prebuilt thing? If you got the same speed back then, I think it might be because of drivers or settings. Has anything in Device Manager had an exclamation mark next to it?

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mickblue2
Junior Member
44
05-08-2026, 10:11 AM
#9
Yeah, I should see the same speed like the notebook did back then. I'm using an MSI B450M Gaming Plus card. Nope, nothing shows up in my Device Manager at all.
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mickblue2
05-08-2026, 10:11 AM #9

Yeah, I should see the same speed like the notebook did back then. I'm using an MSI B450M Gaming Plus card. Nope, nothing shows up in my Device Manager at all.