RT-N66u WAN throughput question

[Matt Storr]

Hi,

I've been using an RT-N66u with AsusWRT-Merlin build 380.57 for quite a while with no issues. I've recently been upgraded to 200/20 Virgin Internet and using their Hub 3.0 I'm able to achieve 222Mb download when my PC is connected to its hub, as well as when I switch the Hub 3.0 into modem only mode and directly connect my PC.

However, when I then connect my Asus RT-N66u to the Hub 3.0 in modem mode, I only get 179Mb download

I'm not using any QoS or other packet inspection and as far as I can see the Asus is using recommended defaults for most items. Is there any reason why the Asus is unable to keep up with the WAN speed or do I need to purchase a new more powerful model (RT-AC68U ?)

 

[RMerlin]

Make sure NAT acceleration is enabled. Check its state on the Tools -> Sysinfo page.

 

[Matt Storr]

Thank you for such a quick response. HW NAT Acceleration was indeed disabled due to the fact I had switched on the "Enable IPTraffic (per IP monitoring)" ability. After disabling that and switching on NAT acceleration, speed jumped considerably :-

I'll run some more tests at different times of the day to see if I can reach the Hub 3.0 222Mb/s speed. As a side note, would the increased CPU power of an RT-AC68u been able to handle this better? For instance, would the dual-core power of the AC68u have allowed me to use IPTraffic and still attain full WAN port speed? I'm thinking the N66u may be a little under-powered for this WAN port speed + packet inspection.

 

[pirx73]

HW NAT Acceleration was indeed disabled due to the fact I had switched on the "Enable IPTraffic (per IP monitoring)" ability.

Same happened to me, i got worried why router's CPU usage is 100% when downloading at full speed of my 100Mbit GPON link, and then saw on Tools->Sysinfo that
"hw acceleration disabled due to iptraffic". After that it was only a matter of removing that checkbox. Not that i need to monitor every IP inside my network
Now CPU usage stays below 30%

 

[RMerlin]

As a side note, would the increased CPU power of an RT-AC68u been able to handle this better?

Yes, the RT-AC68U can handle nearly twice the amount of traffic of the RT-N66U when not using NAT acceleration.

 

[doczenith1]

On my B1 revision 68U (1000 Mhz processor) I was able to get 380 Mbps down and 440 up with NAT acceleration off. With CTF enabled I could get around 940 Mbps both ways.