Extremely slow speed when using VPN!

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Jen1
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Joined: 12 Apr 2020
Posts: 51

PostPosted: Sat Mar 25, 2023 6:34    Post subject: Extremely slow speed when using VPN! Reply with quote
Hey!

I got the old Asus RT-AC88U just to use dd-wrt for the vpn in AP/repeater mode, as asus firmware doesn't support VPN in ap/repeater mode.

Everything is working fine, except it is extremely slow, about 50% to 80% slower from the original speed.

I am using the latest firmware as of today DD-WRT v3.0-r52095 std (03/23/23) with openvpn 2.6.1. the new openvpn 2.6.2 has been released, hope it will be added soon.

What I do believe:

It is not RT-AC88U CPU, as it is only 8-14% when full load.
It is not RT-AC88U RAM, as 83% of RAM is free upon testing.
It is not the client, as I am using OpenVPN on my PC and I am getting 100% of the speed.
It is not the server, on the contrary I am using one server in the router and it is located in my country, while in my PC it is double server and it is not located in my country and I am getting 100% of the speed.

Any idea?

I can accept 30% to 50% slower as I agree to compromise speed for privacy (although I think I should get 100% of the speed) , but 80% slower is too much.

Am I doing anything wrong, cause VPN in router are not that slow!

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Last edited by Jen1 on Thu Apr 13, 2023 18:53; edited 1 time in total
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egc
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Location: Netherlands

PostPosted: Sat Mar 25, 2023 6:42    Post subject: Reply with quote
On OpenVPN my Asus AC68U does about 35 Mb/s, My R7800 (which is much faster than your router) does about 85 Mb/s.

If you want faster use WireGuard which triples that speeds or buy a faster router.

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Routers:Netgear R7000, R6400v1, R6400v2, EA6900 (XvortexCFE), E2000, E1200v1, WRT54GS v1.
Install guide R6400v2, R6700v3,XR300:https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=316399
Install guide R7800/XR500: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=320614
Forum Guide Lines (important read):https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=324087
Jen1
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Joined: 12 Apr 2020
Posts: 51

PostPosted: Sat Mar 25, 2023 6:45    Post subject: Reply with quote
What do you mean buy a faster router? I bought the most expensive one that support dd-wrt, it is old, but high end product!

The CPU will not exceed 15% using even on full load!

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Last edited by Jen1 on Thu Apr 13, 2023 18:52; edited 1 time in total
egc
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Joined: 18 Mar 2014
Posts: 12837
Location: Netherlands

PostPosted: Sat Mar 25, 2023 7:01    Post subject: Reply with quote
OpenVPN is terribly slow because it constantly swaps between user and kernel space and it is not multi threaded so runs only on one CPU.

My advice use WireGuard which triples the speed of OpenVPN, my R7800 does almost 300 Mb/s using WireGuard.

BTW the R9000 is the fastest router which is supported by DDWRT.

_________________
Routers:Netgear R7000, R6400v1, R6400v2, EA6900 (XvortexCFE), E2000, E1200v1, WRT54GS v1.
Install guide R6400v2, R6700v3,XR300:https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=316399
Install guide R7800/XR500: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=320614
Forum Guide Lines (important read):https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=324087
Jen1
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Joined: 12 Apr 2020
Posts: 51

PostPosted: Sat Mar 25, 2023 12:33    Post subject: Reply with quote
I guess I found out why it is so slow!

I am using a vpn on my router and double vpn on my pc! it is like a tor connection!

The server I was using in my router is fast, but when connecting to the servers in my PC it will be slow.

I disabled the VPN in my PC, and tested the VPN in the router alone, it is much faster bu still not getting the full speed, I am getting about 90% of my original speed!

I changed the server in my router, and tested some servers, now I am getting much faster speed.

I guess if I test more I will get full speed eventually, but it is annoying changing the servers in the router. I am happy at 90% of my original speed Smile with the current servers

For now, I am guessing it is just servers issue. I am happy with 90% of the speed using VPN on both my router and double VPN in my PC.

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Last edited by Jen1 on Thu Apr 13, 2023 18:52; edited 1 time in total
dale_gribble39
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PostPosted: Sat Mar 25, 2023 12:48    Post subject: Reply with quote
You will (most likely) never see 100% of your ISP bandwidth using OpenVPN (or even WireGuard) simply because of the cryptography and hardware limitations.
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Jen1
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Joined: 12 Apr 2020
Posts: 51

PostPosted: Sat Mar 25, 2023 13:17    Post subject: Reply with quote
Do you mean I will not get the full speed on routers only or on every platform?

Cause I was getting the full speed on my PC using a double vpn server.

MY VPN provider doesn't provre wireguard on routers at the moment, they will provide it soon.

waiting for OpenVPN 2.6.2 https://github.com/OpenVPN/openvpn/blob/v2.6.2/Changes.rst

I am hoping for support for Data channel offloading!

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Last edited by Jen1 on Thu Apr 13, 2023 18:52; edited 1 time in total
ho1Aetoo
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Joined: 19 Feb 2019
Posts: 2927
Location: Germany

PostPosted: Sat Mar 25, 2023 13:24    Post subject: Reply with quote
Full speed of what?
You haven't written anywhere how fast your internet connection is.
Even a powerful x86 can't manage 1000mbit VPN...
egc
DD-WRT Guru


Joined: 18 Mar 2014
Posts: 12837
Location: Netherlands

PostPosted: Sat Mar 25, 2023 13:24    Post subject: Reply with quote
No there will not be support for DCO as that is only for Kernel 5.x and higher.

Maybe someday someone will backport it.

OpenVPN 2.6.2 is for bug fixes (which there are many Sad )

_________________
Routers:Netgear R7000, R6400v1, R6400v2, EA6900 (XvortexCFE), E2000, E1200v1, WRT54GS v1.
Install guide R6400v2, R6700v3,XR300:https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=316399
Install guide R7800/XR500: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=320614
Forum Guide Lines (important read):https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=324087
Jen1
DD-WRT User


Joined: 12 Apr 2020
Posts: 51

PostPosted: Sun Mar 26, 2023 10:32    Post subject: Reply with quote
I can confirm, in my case it was the servers I was using!

Yesterday, after I change the server in the router it became very fast, but at night it became slow. I changed the server, and it is fast again.


Today I tried another VPN provider, and the results are odd!

In my router I am using provide X connecting to a server not in my country.
In my PC, I am using double VPN from another VPN provider.

And the results are strange using different providers on both PC and router.


The response time is so quick, almost as if I am not using a VPN at all.

I am watching youtube videos with no delay at all for buffering when opening videos. It opens very fast even 4k 60fps.

Internet speed tests give me very slow download and upload (very strange) and the ping time is higher although it is quicker.

Downloading files are slower, but it is acceptable.

The results vary from time to time, but the response time is very quick.

Not sure why using 2 VPN providers game me much faster reponse time. Maybe the servers? If I try more servers using my VPN provider I would get it too?

@egc I am gonna find a VPN provider with WireGuard I am sure it will be faster.

Thanks for the reply.

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Last edited by Jen1 on Thu Apr 13, 2023 18:56; edited 1 time in total
foz111
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Joined: 01 Oct 2017
Posts: 704
Location: Earth

PostPosted: Sun Mar 26, 2023 13:26    Post subject: Reply with quote
"And the results are strange using different providers on both PC and router"
If your referring to the vpn throughput (download speed), your PC VPN throughput will be a lot faster than running the same vpn on your router, your router only has a CPU clock speed of 1.4GHz Most 10+ year old pc will run 2.0GHz let alone newer more modern PC's with a lot faster clock speeds CPU's 3 - 5.0Ghz ish. (Same results running on modern phones)

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Jen1
DD-WRT User


Joined: 12 Apr 2020
Posts: 51

PostPosted: Sun Apr 23, 2023 10:42    Post subject: Reply with quote
OMG, just tried WireGuard and I can't believe what is going on, it is almost I am not using VPN at all.

I am getting now almost the full speed, faster responses ....

@egc thanks for the tip, I should have tried it before.

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egc
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Joined: 18 Mar 2014
Posts: 12837
Location: Netherlands

PostPosted: Sun Apr 23, 2023 11:14    Post subject: Reply with quote
Good to hear Smile

WireGuard is not only much faster but also much easier to install.
Easy to use multiple tunnels, multi site-to-site setup etc.

And of course the ddwrt gui supports policy based routing and much more.

Have fun Smile

_________________
Routers:Netgear R7000, R6400v1, R6400v2, EA6900 (XvortexCFE), E2000, E1200v1, WRT54GS v1.
Install guide R6400v2, R6700v3,XR300:https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=316399
Install guide R7800/XR500: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=320614
Forum Guide Lines (important read):https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=324087
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