Question Lan port only giving 100MPS help!

Jul 11, 2019
Hey all,

I thought for the longest time we had a technical hiccup with the monopoly Comcast, but found my roommate was getting the 250 Mbps wired in, and I'm stuck at 100. We just had them reset the connection, and now even my sister's laptop is at 230Mbps.

This means that:
a) the modem is getting the full connection
b) the cable to the router is also good
c) the router is good

So the only options are
d) my cable to my computer
e) motherboard LAN GB connection

So I have a cat 7 brand new cable, so I don't see that as the problem

This leaves the P5Q-E Asus Motherboard

It has TWO GB LAN ports, and on both of them I can connect and get orange lights (100MBPS). When trying both ports (as it's supposed to allow), it's still the same speed.

Any idea if there is something I can fix or setting I can adjust on this?



Which windows are you running?

Check in advanced properties for the network controller for link speed and duplex and see what the highest value is. Should be 1000 full duplex.

Have you tried another cable?, not that cat7 can't handle the speeds, it's quite excessive actually for gigabit since cat5 can do gigabit. Just to check there's not a fault with the cable. For gigabit, all 8 wires are used and if there's the slightest fault with any of those wires the negotiation speed will drop to megabit / 4 wires.

How long is the cable you're using?
First be sure to check the setting in your nic and make sure it is set to auto. Anything else runs the risk that the router which is running auto will get confused and drop port to 100mbps.

It almost has to be the cable. It is not common for a new cable to be bad but it happens. Be very sure you are not using fake cable. The cable must be pure copper, no cca. It also must be wire size 22-24 so no thin or flat cable. This stuff is marked on side of most cables along with the marking eia/tia but even fake cable put that on even though they are not certified cables.

The problem with cables that are bad for one reason or another is they work on some machines but not others. The equipment to actually test a cable and make sure it can pass data correctly is very expensive.

It is fairly cheap to buy another cable. You do not need cat7 to run gigabit ethernet. It is designed for 10g and you only get that if you have 10g ports. I would get cat5e or cat6 if it is cheaper. There is no real benefit to cat6 cable. Be very sure it is not fake cable read the specs and do not buy it if you can tell.
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