Netgear R7800 ethernet port speed max 100Mbps

[RJU118]

Is about a Nighthawk(R) X4S R7800  firmware version V1.0.2.40

Although a gigabith ethernet connection from the modem is connected to the wan port and a gigabit switchport is connected to ethernet LAN port 1, both show a maximum of 100Mb.

Also the connected Gigabit switch port shows a maximum of 100Mb. (connecting other gigabit devices on the switcvh port show a 1Gbps speed)

According to the specs , the ethernet ports of the R7800 are 1Gbps.  What can be the cause that the bandwidth is max 100Mbps ?

router status  /  internetport statistics:

[TheEther · Accepted solution]

One possibility are bad cables. Gigabit Ethernet uses all 4 wire pairs (8 wires) inside the cable. If one or more wires are faulty, then speeds can drop down to 100 Mbps, which only requires 2 wire pairs (4 wires).

Another possibility is that Ethernet autonegotiation is failing. This is uncommon but it still seems to happen. AFAIK, the Nighthawk doesn't have any settings to control autonegotiation, nor do most modems. One trick that can work is to put a switch in between. The switch may do a better job of autonegotiation than the two devices it is interconnecting. Obviously, this doesn't explain why your existing switch can't negotiate a 1 Gbps speed with your Nighthawk.

I would first try new cables since that's relatively inexpensive. Good luck.

[TheEther · Accepted solution]

One possibility are bad cables. Gigabit Ethernet uses all 4 wire pairs (8 wires) inside the cable. If one or more wires are faulty, then speeds can drop down to 100 Mbps, which only requires 2 wire pairs (4 wires).

Another possibility is that Ethernet autonegotiation is failing. This is uncommon but it still seems to happen. AFAIK, the Nighthawk doesn't have any settings to control autonegotiation, nor do most modems. One trick that can work is to put a switch in between. The switch may do a better job of autonegotiation than the two devices it is interconnecting. Obviously, this doesn't explain why your existing switch can't negotiate a 1 Gbps speed with your Nighthawk.

I would first try new cables since that's relatively inexpensive. Good luck.

[RJU118]

Thanks for your answer.

After posting I realised that I used for a part of my network a bundel of cat 5 cabling and maybe only connected two pairs on some connections (years ago 🙂  ). So this must be the solution, thanks for reminding me, I'm gonna investigate..