F5F Stay Refreshed Power Users Networks Here is a new cable modem? That might take time if your internet is slow today.

Here is a new cable modem? That might take time if your internet is slow today.

Here is a new cable modem? That might take time if your internet is slow today.

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KayaChan_
Member
206
07-28-2026, 07:56 AM
#1
I have a plan that offers up to 400Mbps with Xfinity, but my speedtest shows only about 100Mbps when using a direct ethernet cable. Xfinity emailed me saying they need a better modem because of this gap. I'm not sure if the new modem is the real problem since my old Netgear CM500-100NAS can handle up to 370 Mbps on its own. The numbers don't add up, though, so maybe something else is going on?
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KayaChan_
07-28-2026, 07:56 AM #1

I have a plan that offers up to 400Mbps with Xfinity, but my speedtest shows only about 100Mbps when using a direct ethernet cable. Xfinity emailed me saying they need a better modem because of this gap. I'm not sure if the new modem is the real problem since my old Netgear CM500-100NAS can handle up to 370 Mbps on its own. The numbers don't add up, though, so maybe something else is going on?

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AlexPFM7
Member
52
07-30-2026, 07:29 AM
#2
This means you might have a broken cable or an old internet switch. The equipment isn't fast enough for high-speed connections.
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AlexPFM7
07-30-2026, 07:29 AM #2

This means you might have a broken cable or an old internet switch. The equipment isn't fast enough for high-speed connections.

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Nejc007
Senior Member
707
07-30-2026, 07:46 AM
#3
This means your cable or internet plug isn't working right, and something in that line isn't fast enough for gigabit speeds.
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Nejc007
07-30-2026, 07:46 AM #3

This means your cable or internet plug isn't working right, and something in that line isn't fast enough for gigabit speeds.

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Phade2002
Member
67
08-10-2026, 10:14 PM
#4
Alright, I'm going to grab a fresh ethernet cord and see if it works better.
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Phade2002
08-10-2026, 10:14 PM #4

Alright, I'm going to grab a fresh ethernet cord and see if it works better.

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Kento11
Junior Member
6
08-11-2026, 12:04 AM
#5
Solid Cat5e cable. It isn't flat, and it's definitely not a copper-clad aluminum type.
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Kento11
08-11-2026, 12:04 AM #5

Solid Cat5e cable. It isn't flat, and it's definitely not a copper-clad aluminum type.

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encoder92
Member
66
08-12-2026, 11:43 PM
#6
Got a Cat8 cable, so it really helped me speed things up. Now I'm getting over 400 Mbps.
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encoder92
08-12-2026, 11:43 PM #6

Got a Cat8 cable, so it really helped me speed things up. Now I'm getting over 400 Mbps.

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Lubmo
Member
190
08-13-2026, 12:23 AM
#7
Unless you spent around $50 for a 10-foot cable, it probably isn't a real Cat8 cable. Real Cat8 cables only come from special shops used in data centers, so almost everything else on sites like Amazon is fake. Maybe you got a Cat5e cable and it was called Cat8; that's fine because you can't use anything better than Cat5e anyway. What's more likely? The cable might just be made of impure copper or the wire size isn't between 22 to 24 inches. Fake cables often work at short distances on some stuff but not others, so it doesn't matter much since they aren't official. You could get a random problem if you're lucky; sometimes it works fine and other times it won't. You might just have overpaid.
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Lubmo
08-13-2026, 12:23 AM #7

Unless you spent around $50 for a 10-foot cable, it probably isn't a real Cat8 cable. Real Cat8 cables only come from special shops used in data centers, so almost everything else on sites like Amazon is fake. Maybe you got a Cat5e cable and it was called Cat8; that's fine because you can't use anything better than Cat5e anyway. What's more likely? The cable might just be made of impure copper or the wire size isn't between 22 to 24 inches. Fake cables often work at short distances on some stuff but not others, so it doesn't matter much since they aren't official. You could get a random problem if you're lucky; sometimes it works fine and other times it won't. You might just have overpaid.