Interesting VPN Speed Loss on Asuswrt-merlink

[anonymoose]

Hi Guys,

The long and short of it, I had ADSL2+ and got upgraded to fibre.

ADSL2+ (Private Internet Access VPN)
Desktop Client
Without VPN: 7Mbps
With VPN: 1Mbps

When the fibre upgrade happened, bought a shiny new R7000 Nighthawk, flashed it with Asuswrt-merlin 380.58 and setup a new VPN service on OpenVPN client (to protect any device connected to my network).
A friend also suggested changing from PIA to IPVanish.

Fibre 50Mbps (IPVanish)
OpenVPN on R7000
Without VPN: 48Mbps
With VPN: 32Mbps

Now as I was so happy to be off ADSL never thought to question the difference between speeds with or without VPN on Fibre50. However I have just upgraded my plan and this interesting thing happened:

Fibre 100Mbps (IPVanish)
OpenVPN on R7000
Without VPN: 91Mbps
With VPN: 32Mbps

I was very confused so I did the only thing I could think of and that was to download IPVanish's desktop client to check server congestion and see what the speed difference was:

Fibre 100Mbps (IPVanish)
Desktop Client - Windows 10 Home 64bit
Without VPN: 91Mbps
With VPN: 82Mbps

That seemed like a much more reasonable result but begs the question why the OpenVPN drop in Merlin on the R7000? Is it something I have setup or configured incorrectly in OpenVPN?

All speedtests were run via Ookla (http://speedtest.net) and the above speeds were averaged and rounded down.
All speed testing was performed with only one device connected to the network and connected directly to the router by 1Gbps Cat6 Shielded Ethernet.

I'm hoping this is something that can be easily resolved, tbh I hope I have set something up wrong or maybe it is a known bug. Any advice would be helpful. I'm happy to provide any and all technical information you require.

Thankyou in advance!

 

[john9527]

Two things......
(1) Merlin doesn't support the R7000, only ASUS routers. You should contact the owner of that fork for support.
(2) The VPN results are as expected. The processor in the routers just doesn't have the horsepower to support fast VPN connections.

 

[anonymoose]

(1) Fair enough.
(2) The Nighthawk has a dual-core processor with 250MB of RAM and was being touted as one of the best routers for OpenVPN as far as I was aware at the time of purchase. I tried to max out my connection today with x21 downloads running simultaneously with files sizes of 300MB up to 1.3GB averaging 100KB/s per DL, plus streaming a 4K HDR sample from Youtube. I was still able to get a 17ms Ping and 19Mbps download rate from speedtest.net

Ignoring the fact that it is an unsupported router - the current hardware should physically be able to handle a 100 Mbps VPN connection. As you can see here whilst all that activity was going on this was what the CPU was doing:

I may not be an expert but it certainly doesn't seem to be struggling, is it likely I may have something in Merlin configured incorrectly for IPVanish?

 

[cybrnook]

Your results are normal, you will not get more than 35~ Mbps on this platform. It will NOT sustain 100Mbps, look into pfsense if you need that.

Also keep in mind OpenVPN is single threaded, so only one core will even be handling your tunnel.

If you search around, you will see this has been discussed to death by now.

 

[anonymoose]

Ok thanks