N66U problem with ethernet speed limited to 100 Mbps

[knecke]

Hello!
I have the (quite old) Asus N66U router which works fine for me, except one thing.

For some reason, my LAN ports seem capped out at 100 mbits.

I have reset the router and using the stock firmware version 3.0.0.4.382_52272

I'm currently paying for 500 mbit/s, and when I connect my computer directly to the modem through my LAN cable (cat 6) I get about 300 mbit/s speeds.

But when I connect through my router, it slows down to about 95mbit/s.
In my router, when I go to System Status > Status and then Ethernet ports, it states:
WAN 1 Gbps
LAN 1 100 Mbps
Lan 2 Unplugged
LAN 3 100 Mbps
Lan 4 Unplugged

So for some reason, my LAN ports won't go above 100 Mbps? Even tough I have double checked, all my cables are Cat6, and when connecting with these cables directly to my modem, I get the higher speeds.

I have QoS turned off, with NAT Acceleration (hardware acceleration?) turned on, together with CTF.

So I really don't understand why it's being limited to 100 Mbps.

 

[L&LD]

Test with a quality Cat5e Ethernet cable instead. Sometimes, it's not the cable grade, it is the connectors on the ends that are not a good fit with all routers/devices.