AC1200 R6120 Router Slowing Down Internet

[Previzionn]

I just bought an Arris SURFboard 32x8 cable modem (SB6190) and a Netgear AC1200 (R6120) router. The firmware that is on my router is V1.0.0.36. When I am plugged in directly to the modem, I am getting ~350Mbs. When I am connected to the router, I am only getting ~90Mbs. Any ideas on what might be going on and how I can fix it? 

[Previzionn · Accepted solution]

I figured out what the problem is. I am just an idiot that did not read the box carefully. The box says it supports 300 + 900 Mbps on the front, but on the side it says that the LAN throuput is only 100 Mbps.

[michaelkenward]

Things that people have tried to fix the "router is throttling my modem" issue with various devices:

• Ensure that the cable from the router to the modem is up to the job
• Check that you have the latest firmware (and "factory reset" the device)
• Check that you have the right internet settings for your ISP (especially MTU)
• Turn off QoS
• Turn off the Traffic Meter

Netgear also advises that you should turn off QoS if you are on Gigabit Internet. You don't need it.

[Previzionn]

I tried everything you suggested except for turning off QoS and the Traffic Meter and have not had any success at improving the speeds. When I Google how to turn of QoS and the Traffic Meter, it tells me sign in at www.routerlogin.net. Then, I should go to Advanced and I should be able to find QoS under Setup and Traffic Meter under Advanced Setup; however, these do not exist for me. I cannot find them anywhere else. Do you have any suggestions?

[Previzionn · Accepted solution]

I figured out what the problem is. I am just an idiot that did not read the box carefully. The box says it supports 300 + 900 Mbps on the front, but on the side it says that the LAN throuput is only 100 Mbps.

[michaelkenward]

I am surprised that Netgear still sells devices that run that slow.

Looking at the manual, the specifications say that the LAN and WAN ports are 10BASE-T. This is hard to believe. Most now support 1000BASE-T.