RT-AC68U 60% bandwidth loss when OpenVPN client turned on

[BigSnicker]

I'm wondering if anyone else has seen this, but my new RT-AC68U seems to have a 60% performance hit when I use its OpenVPN client.

Graphic of the various results here: http://postimg.org/image/ocii1ahfl/

As shown above, the performance hit occurred only for the router's OpenVPN client, as its L2TP worked fine and other OpenVPN clients tested on the network worked fine as well. The test results were consistent across multiple VPN servers and the CPUs never went above 10% utilisation during the testing.

Any ideas? Surely this can't be the generally accepted performance of this router.

P.S. Using latest stock firmware, will probably see if Merlin improves the situation if I don't find any good solutions with the existing firmware

 

[sfx2000]

Isn't there another thread on this topic?

 

[BigSnicker]

I don't think so. I couldn't find any active discussion on the topic, and the closest inactive ones I found were the following:

http://www.snbforums.com/threads/rt-ac87-aiprotection-is-throttling-my-openvpn-client.29557/ - Guy who has an even larger degradation that he attributes to aiprotection

http://www.snbforums.com/threads/openvpn-vs-l2tp-speed-with-router.23041/ - Exactly the same problem, but a year old and unresolved

http://www.snbforums.com/threads/asus-rt-ac87u-openvpn-speeds.29356/ - Active thread, but much higher bandwidths being tested and a different model of router that ends up just looking like a dud

 

[BigSnicker]

Ahhhhh, I think I found the relevant thread in the Merlin firmware subgroup. I was having the same issues with the stock firmware, but hopefully the recommendations will be the same:

http://www.snbforums.com/threads/openvpn-performance.21023/

However, when I try to use their recommendation to shut off the NAT H/W acceleration, I run into my next problem....

http://www.snbforums.com/threads/advanced-functions-on-rt-ac68-invoke-screen-of-death.30785/