RT AC66U Fast Upload & Slow Download speed with latest 4_376.47_0

[headroot]

I've just ordered RT AC66U and I'm frustrated. I started from latest FW from asus. At second step I've flashed with latest RT-AC66U_3.0.0.4_376.47_0.zip.

I've disabled 2,4 GHz at all, also I'm using default settings for 5GHz.
For first 10 minutes it's worked on on all cylinders.
It was getting all speed from uplink in my case it 80Mbs.
But after a little break, on next attempt to check it speed, it shows 9Mbs per download, and 80Mbs per upload.

Please help me what I do wrong with this hardware.
It seems I tried everything...

 

[SavageWS6]

I've just ordered RT AC66U and I'm frustrated. I started from latest FW from asus. At second step I've flashed with latest RT-AC66U_3.0.0.4_376.47_0.zip.

I've disabled 2,4 GHz at all, also I'm using default settings for 5GHz.
For first 10 minutes it's worked on on all cylinders.
It was getting all speed from uplink in my case it 80Mbs.
But after a little break, on next attempt to check it speed, it shows 9Mbs per download, and 80Mbs per upload.

Please help me what I do wrong with this hardware.
It seems I tried everything...

Is QoS enabled? It's located under Traffic Manager, if so disable it and see if it fixes the issue

 

[headroot]

QoS is disabled. But there are no any good changes.

 

[SavageWS6]

QoS is disabled.

Now check under LAN tab > Switch Control. I'm using a AC-68R, but should be simular. My settings are

Enable Jumbo Frame - Enable
NAT Acceleration - Enable
Spanning-Tree Protocol - Disable

I haven't figured out why these routers do it yet.

Maybe try flashing a Merlin build and see if it fixes the issue also

 

[headroot]

Thanks, I'll try.

Maybe try flashing a Merlin build and see if it fixes the issue also

I'm already on Merlin it's RT-AC66U_3.0.0.4_376.47_0.zip
I need to say thanks him, I'm starting to use it in case that I was need stealth mode, which is working good.

 

[SavageWS6]

Thanks, I'll try.

I'm already on Merlin it's RT-AC66U_3.0.0.4_376.47_0.zip
I need to say thanks him, I'm starting to use it in case that I was need stealth mode, which is working good.

If that doesn't fix the issue then try firmware 1 step down which I'm using 376.45 and I haven't had 1 issue yet (If you have that option)

 

[headroot]

SavageWS6
Thank you for your helping. My problem was solved with your findings, even without switching to previous version. Now it works as expected!

 

[SeCrEt_BoY]

SavageWS6
Thank you for your helping. My problem was solved with your findings, even without switching to previous version. Now it works as expected!

Share your findings!