Do you have any other device in your home that you know is gigabit capable? If so, is it possible for you to use the same cables and connect to another device and see if you get a 1Gbps link? Usually TVs with gigabit ports can tell you what the connection speed. Or you may be able to see the connection speed if you log into the router management interface.
There is also the possibility that the NIC speed on your laptop is set to 100mbps. It might be worth double checking that just to eliminate that possibility, and if it is, set it to auto. And while checking that, make sure the duplex is set to auto.
If the same cables give you gigabit speed with other devices, and the NIC speed and duplex is good, take a look at the pins on the rj45 port on your laptop, make sure they look good and not broken/bent. If they look good as well, then go to ASUS's website and download the latest LAN drivers. Then uninstall the current driver's for the network adapter and install the newly downloaded drivers.
If that still doesn't work, last thing to check is if your laptop gives you a gigabit connection elsewhere. Maybe go to a friend's house and use a cable they might have and test it.
If it still doesn't work, then it's likely your Ethernet port is fault. Only option would be to either get ASUS to replace the laptop if it's under warranty otherwise, get it repaired out of warranty, although that might cost a fair bit of money. Cheapest option would be to purchase a USB3.0 to RJ45 Gigabit adapter (making sure to use a USB 3 port).
Do you have any other device in your home that you know is gigabit capable? If so, is it possible for you to use the same cables and connect to another device and see if you get a 1Gbps link? Usually TVs with gigabit ports can tell you what the connection speed. Or you may be able to see the connection speed if you log into the router management interface.
There is also the possibility that the NIC speed on your laptop is set to 100mbps. It might be worth double checking that just to eliminate that possibility, and if it is, set it to auto. And while checking that, make sure the duplex is set to auto.
If the same cables give you gigabit speed with other devices, and the NIC speed and duplex is good, take a look at the pins on the rj45 port on your laptop, make sure they look good and not broken/bent. If they look good as well, then go to ASUS's website and download the latest LAN drivers. Then uninstall the current driver's for the network adapter and install the newly downloaded drivers.
If that still doesn't work, last thing to check is if your laptop gives you a gigabit connection elsewhere. Maybe go to a friend's house and use a cable they might have and test it.
If it still doesn't work, then it's likely your Ethernet port is fault. Only option would be to either get ASUS to replace the laptop if it's under warranty otherwise, get it repaired out of warranty, although that might cost a fair bit of money. Cheapest option would be to purchase a USB3.0 to RJ45 Gigabit adapter (making sure to use a USB 3 port).