VPN Throttling

[Weggy]

Issue:
My internet download speed appears to be throttled somehow (uncertain how) when utilising a VPN via my router. My NAS is setup to ensure all traffic goes via my VPN using Open VPN and strict policy rules. However, when connection via the VPN my speeds are around 50% of what they should be and there is no clear sign as to why this is (at least I've run out of ideas). I'm 100% sure (I think ) it's not my service provider (PIA), I double checked this theory by trying another provider (privado) and the issue still persist. I can only assume the issue is my end.

Setup:
Router: Asus RT-AC5300 (Firmware Version:384.18)
Internet Down\Up Speed: 114Mbps\5Mbps
NAS: Synology DS1019+
VPN Service: Private Internet Access

Does anyone know if this is a known issue with the firmware I'm using or if I might have made a mistake in my setup which is why I'd be getting an issue like this.

Any help would be greatly appreciated as I'm completely out of ideas (googling) to fix this issue.

 

[L&LD]

Are you saying you're achieving around 50Mbps with VPN connections? If so, that is the limit of your router's hardware.

 

[Weggy]

I can achieve over 100Mbps without a VPN running on my Asus RT-AC5300.

With a VPN active, the speed drops to ~50Mbps.

 

[ColinTaylor]

With an RT-AC5300 the most you will get is about 60 to 70 Mbps (possibly slightly less because of your generally slow connection).

 

[Weggy]

"With an RT-AC5300 the most you will get is about 60 to 70 Mbps."
How are you calculating that? And do you mean with or without a VPN?

 

[L&LD]

Yes, you've reached the limit of your hardware with that provider and servers tested.

If you want to have 200Mbps or faster, an RT-AC86U, RT-AX86U, or an RT-AX88U will give you the performance you need to potentially not be bottlenecked by the hardware.

(Potentially, because it still depends on the other end you connect the VPN too).

 

[ColinTaylor]

"With an RT-AC5300 the most you will get is about 60 to 70 Mbps."
How are you calculating that? And do you mean with or without a VPN?

The VPN speed is limited by the speed of your router's CPU. I can get about 55 to 60 Mbps before hitting my router's CPU limit. Your router's CPU is 16% faster than mine.

 

[Weggy]

The VPN speed is limited by the speed of your router's CPU. I can get about 55 to 60 Mbps before hitting my router's CPU limit. Your router's CPU is 16% faster than mine.

I'm not sure this is true (nor wrong ). But I've tried moving the VPN off the router and onto my NAS (far more powerful CPU) and the results are the same. In this case, surely all the router is doing is transferring the data?

 

[ColinTaylor]

I'm not sure this is true (nor wrong ). But I've tried moving the VPN off the router and onto my NAS (far more powerful CPU) and the results are the same. In this case, surely all the router is doing is transferring the data?

Then that would be a different issue. The various routers' throughput performance is well known and has been discussed in detail for many years.

 

[ColinTaylor]

But I've tried moving the VPN off the router and onto my NAS (far more powerful CPU) and the results are the same.

What throughput do you get when running the VPN client on a desktop PC?

 

[Weggy]

What throughput do you get when running the VPN client on a desktop PC?

On PC even when wireless via the VPN connection PIA app I get around 90% connection speed (which could easily be wireless more than the VPN))

 

[L&LD]

Sounds like you're misconfiguring something then on the router and/or the NAS (btw, which model do you have)?

 

[Weggy]

Sounds like you're misconfiguring something then on the router and/or the NAS (btw, which model do you have)?

Router: Asus RT-AC5300 (Firmware Version:384.18)
NAS: Synology DS1019+

 

[Weggy]

I think I've got it working via running the VPN on the NAS. What did I do? Turn it off and on again. FML

 

[eibgrad]

I'm not sure this is true (nor wrong ). But I've tried moving the VPN off the router and onto my NAS (far more powerful CPU) and the results are the same. In this case, surely all the router is doing is transferring the data?

The problem is not just a matter of transferring data, but how that data is managed in the non-VPN vs. VPN modes. And it's not just the CPU itself, but the overall system architecture used on the router compared to say a full-blown desktop (x86).

ExpressVPN setup (app vs. manual configuration) in Asus routers

Hi, I have the ExpressVPN app installed in my Asus RT-AC87U and it performs very well with averages download speeds for the server I use at about 30Mbps (ISP ~60 Mbps). The ExpressVPN app is built on a DD-WRT platform but I was curious how some (or all) of its settings could be translated in...

www.snbforums.com

 

[Mark2020]

Hey All, I have a similar issue...but worse and I really appreciate any help or guidance.
I'm using Asus AC5300 with Asuswrt-Merlin 384.19. I'm connected to a high-speed internet of 1Gps (1,000 Mbps). when I use a VPN, my internet speed drops to 20-35MBps and im not sure why ?
The speed without VPN is - 943Mbps
The Speed with Window VPN app |( IKve2) - is 464Mbps ( I don't want to use this option as I have 15+ devices,,,)
The Speed with OpenVPN on the router is 20-35MbPS

Plz see include the speed info and the router setup including VPN
Setup : https://support.ipvanish.com/hc/en-...Configure-IPVanish-OpenVPN-in-ASUSWRT-Merlin-

Any Help is welcome and appreciated!

Tnx
Mark

 

[L&LD]

Have you tried different servers? Different types of encryption?

Are you also running other features/options on the router?

If so, that is all you can expect from the hardware.

 

[isr25]

This is normal as AC5300 unfortunately does not have AES-NI acceleration for VPN. But even with hardware accelerated VPN from the latest routers, you may only get around 300Mbps.

 

[Mark2020]

Have you tried different servers? Different types of encryption?

Are you also running other features/options on the router?

If so, that is all you can expect from the hardware.

yes, I did try the above ...but didn't got any change...
I did got a small change when I used different clients like PPTP/L2TP... which brought the speed to 100Mbps... but it’s incredibly insecure.
Do you know how I can add IKEv2/IPSec as an option on the VPN client? or look into a WireGuard... this can help a bit...?

 

[Mark2020]

This is normal as AC5300 unfortunately does not have AES-NI acceleration for VPN. But even with hardware accelerated VPN from the latest routers, you may only get around 300Mbps.

Thank you, can u share your favorite for a router with AES-NI acceleration that can work with Merlin software ? its will be great to have at least 300Mbps...

here a few that i found:

devices are using these Broadcom processors?

Asus RT-AC68U Extreme
Asus RT-AC86U (AC2900 version)
Asus GT-AC5300
Asus GT-AX11000
Asus RT-AX95U
Asus RT-AX88U
Arris SurfBoard W31
D-Link DIR-X6060