RT-AC88U went from 800Mbps to 520Mbps with Cox Gigablast

[TimRedBeard]

My current setup is a Netgear CM1200 Modem with Cox Gigablast and I'm running a RT-AC88U with Asuswrt-Merlin 384.19. I was having great download speed between 800-920 down without issues. My upload speeds have been consistent at 35 up. However now I can't get my speeds above 520 down at all. I've done everything I can think of. I've searched the forums and tried every kind of settings that I've found to try and get the best speeds. Does anyone have any suggestions on how to help me get better download speeds?

QoS is off
AiProtection is off
Jumbo Frame - Disabled
NAT Acceleration - Auto (CTF is enabled)
Spanning-Tree Protocol - Enabled
Link agg - Disabled
Enable WAN - Yes
Enable NAT - Yes
UPnP - No
Connect DNS Server Automatically - Yes

Any help would be great, I don't know what else I can do except reset the router and start fresh. Thank you in advance.

 

[L&LD]

Troubleshooting 101 Asus/RMerlin Routers 2020

Top 10 Simple Asus/RMerlin firmware powered Router Troubleshooting steps to try first: NOTE: Although this is for Asus/RMerlin-firmware powered routers, the steps below may be relevant to all routers, to get to a quick fix for common symptoms. Check that the router’s System Time is accurate on...

www.snbforums.com

 

[degrub]

check what the speed is directly connected to the modem to see in which of the two the problem lies.

 

[pencilhead]

Turn off spanning tree unless you have bonded links or something like a NAS with 2 interfaces. Link agg is off. It's not needed for single connected devices where there is no chance of a loop.

 

[ddaenen1]

My current setup is a Netgear CM1200 Modem with Cox Gigablast and I'm running a RT-AC88U with Asuswrt-Merlin 384.19. I was having great download speed between 800-920 down without issues. My upload speeds have been consistent at 35 up. However now I can't get my speeds above 520 down at all. I've done everything I can think of. I've searched the forums and tried every kind of settings that I've found to try and get the best speeds. Does anyone have any suggestions on how to help me get better download speeds?

QoS is off
AiProtection is off
Jumbo Frame - Disabled
NAT Acceleration - Auto (CTF is enabled)
Spanning-Tree Protocol - Enabled
Link agg - Disabled
Enable WAN - Yes
Enable NAT - Yes
UPnP - No
Connect DNS Server Automatically - Yes

Any help would be great, I don't know what else I can do except reset the router and start fresh. Thank you in advance.

So this happened overnight, without any changes to hardware or provider, right? I would have done a reboot already. When i owned an AC88u, this was my first remedy. Pull out the power supply plug, wait 30 seconds and plug it back in. It was the fix for most issues. Also the reason why it is gone now.