Hello, I am from Europe Romania, and have an older ASUS model (RT-AC55U), which worked more than fine, even on 5GHZ (with its limitations, of course).

The thing is i upgraded (i don't know why to be honest) to the latest firmware version 3.0.0.4.382_51812 and then the LAN speed downgraded from 8-900 Mbps (we have real high speed internet here in Romania, and i have the 1 Gbps connection) to 300-320 Mbps. If I connect the cable directly to the huawei provider's I Have 900 Mbps, but if I connect it back to the Asus router, I can't seem to get more than 320 Mbps.

Again, last week everything was working normally.

I have looked through the settings, I have tried with the Jumbo Frames and NAT acceleration on AUTO, QOS is off...i don't know that to do anymore, so please if you can help me out with any suggestions ?

Thank you in advance! Alex

If you are reffering only to 800 - 820 Mbps, i think it is a limitation from the ISP, sometimes 900 Mbps, but never 1 Gbps, anyway if you are talking about this, well then this is not the problem I am complaining about, as I am OK with 800-820Mpbs and not with 300-320-maybe a max of 330 Mbps

I was thinking maybe trying a different firmware (al older one) but couldn't find any for sure, fortunately

Hello Asus,

Thank you for your help. I have contacted Merlin and he gave me a beta version of this firmware, I will try and install it and see what I can do.

Unfortunately, on the link you gave me it's the same version I have installed (without NAT acceleration, "Merlin" says ... and btw - it's just a very big coincidence that we use the same nickname!!!)
-> https://www.asus.com/Networking/RTAC55U/HelpDesk_Download/

ASUS RT-AC55U Firmware version 3.0.0.4.382.51812 with the version from the web interface from my router -> Operation Mode:Wireless router Firmware Version:3.0.0.4.382_51812

Anyway, 2 and 3 were already made, with the exception that NAT Acceleration may not be working probably...

Of course, didn't take any factory reset, I though that maybe it can work without any...

LE: with the firmware that Merlin send me, it worked!!! Without any factory reset.

Hmm...so...the question could be? why did you release an official firmware without NAT acceleration ?

I know there is, there was also an option for NAT Acceleration, the thing is ...it just didn't work, probably had a bug in the firmware. Please release a new one, maybe it can also help for some other users. Thank you and goodluck !