N66U VPN client limitations

[cowst]

Hi,
I have my VPN capped always at 15mbit (on 120 available), and I thought they were throttling traffic although they say they don't.

Today I realized that my router might be the issue, so I tried:
- vpn on router: >85% cpu, 15mbit
- vpn on laptop: <1% cpy, 62mbit
- no vpn: <1% cpu, 95mbit

So I think the first measurement shows a possible cpu culprit for my lack of speed.

Does anybody know if this is actually true and whether it can be mitigated somehow?
A friend of mine with a 60€ mikrotik (https://routerboard.com/RB951G-2HnD) with same nominal cpu speed 600mhz claims to have full 240mbit.

 

[Zirescu]

You're going to be limited by the CPU on the N66U. What client are you using and what encryption settings, ditto for the friend? With the N66U you'll max out around 20Mbit down. Do you have the hardware acceleration enabled? What firmware version are you running?

 

[john9527]

- vpn on router: >85% cpu, 15mbit

That's as good as it gets. At 15Mbps, I think you are actually at the very top of what to expect from an N66

 

[CaptainSTX]

That's as good as it gets. At 15Mbps, I think you are actually at the very top of what to expect from an N66

I concur with my N66 15 Mbps is the best I can do. I moved to a faster processor on an AC1900P and that will get me to 55 Mbps.

 

[cowst]

Thanks guys, good to know.
My friend later specified he uses pptp, which should make quite a difference, although I wouldn't have expected 240mbit
For completeness:
- NordVPN defaults: AES-256-CBC
- Merlin's fork from John v23
- HW accel enabled I believe

Such a nice router, and now I have to question it...

 

[Zirescu]

PPTP doesn't do any encryption by itself so this is why he's getting those types of speeds. You might get a little better performance by choosing a lower encryption level. You can check if the HW acceleration is enabled by looking on the Tools->System Information page near the bottom.

 

[cowst]

I'd rather not lower the encryption level, to be honest I think whatever traffic I have on the devices behind VPN can cope with 15mbit, I was just doing the math when I thought about CPU limitation and my VPN capped at 15mbit, so I wanted to confirm that is the reason
HW accel is on.