Slow OpenVPN server on Asus RT-AX86U

Seamus

New Around Here
I have try to find any useful information for my problem. But at the end I am out of idea.
I recently bought TP-Link Archer C7 V5 (AC1750) and I put Gargoyle firmware and start OpenVPN server. Soon realize that speed is very slow - around 2MB/s.
I've done resarch and I found out that I bought wrong router.

So I bought this one bellow and put latest Merlin on it.

1648646643912.png


BUT - the speed is the same cca 2MB/s. I am connected to 200/20Mbit/s optical line and regarding this both speeds (UL/DL) are more or less the same.

In this RT-AX86U I can also monitor CPU usage - there is almost no CPU usage:
1648646923149.png


Otherwise, everything is working great - several clients, connected two locations (this router servers as server, while RT-AX58U is client) . Everything is visible and connectable as planed. Stable connection. All OK. So OpenVPN is configured correctly.

Except speed.

What am I doing wrong?
I am using AES-GCM, both 128 and 256 encryption, no difference, I also try AES-128-CBC, no difference.

I would be very grateful for any information what to do, for speeding up the transfer.
 

Tech9

Part of the Furniture
I would be very grateful for any information what to do, for speeding up the transfer.

Transfer to what device? The RT-AX58U router or something else?
 

ColinTaylor

Part of the Furniture
What is RT-AX58U upload and download speeds?

Are you testing the speed from the RT-AX86U server or to the server?

If you are doing an "internet speed test" on your client device then the reported speed is correct. You will be limited by the 20Mbit/s upload speed (to the VPN client) of the RT-AX86U. The 2.22 MB/s in your screen shot is ~18Mbps (when using a VPN the throughput can sometimes be misreported as a download).
 
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Seamus

New Around Here
Transfer to what device? The RT-AX58U router or something else?
Doesn't matter. To other router - RT-AX58U, or if I conect my laptop over OpenVPN Client (so router is without direct VPN connection, just plain router), I can connect the same laptop over mobile network, so not fixed internet.
Always excatly the same results aprox. 2MB/s.
 

Tech9

Part of the Furniture
To other router - RT-AX58U

Then everything is working as expected. As @ColinTaylor pointed out, you are limited by your ISP upload speed of 20Mbps or about 2.4MB/sec max. The 2.22MB/sec transfer you see is realistic expectation. I get about 3.4MB/sec from my 30Mbps upload, for example.
 
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Seamus

New Around Here
What is your VPN client device? What is this device's upload and download speeds?
Laptop on fixed internet or over mobile 4G connection, mentioned router.
4G connection is
1648649788019.png

but still 2MB at router.

Are you testing the speed from the RT-AX86U server or to the server?
Both - computer speed (windows speed on transfering file) and speed on router - the picture in first post, are more or less the same, minor differences.
If you are doing an "internet speed test" on your client device then the reported speed is correct. You will be limited by the 20Mbit/s upload speed (to the VPN client) of the RT-AX86U. The 2.22 MB/s in your screen shot is ~18Mbps (when using a VPN the throughput is misreported as a download).
Yes, I know, that's why I try to utilize connection in both directions - it should be 2MB up / 2MB down , but it was unstable connection with sum around 2MB/s.
 

Seamus

New Around Here
Then everything is working as expected. As @ColinTaylor pointed out, you are limited by your ISP upload speed of 20Mbps or about 2.4MB/sec max. The 2.22MB/sec transfer you see is realistic expectation. I get about 3.4MB/sec from my 30Mbps upload, for example.
OK. I will try tomorrow another test, to include third client (laptop) with another connection, since on download to RT-AX86U there is still some room and 4G it seems pretty unstable for upload.

Thanks for very fast reply's.
 

ColinTaylor

Part of the Furniture
Yes, I know, that's why I try to utilize connection in both directions - it should be 2MB up / 2MB down , but it was unstable connection with sum around 2MB/s.
Sorry, but this seems to be a different problem now. You were complaining that the VPN speed was only 2MB/s but it was stable. But now you're saying your client connection is only ~3MB/s (25Mbps minus protocol overheads) so I'm not sure what more you're expecting when the router's upload is only 20Mbps (<2.5MB/s).
 
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Seamus

New Around Here
Sorry, but this seems to be a different problem now. You were complaining that the VPN speed was only 2MB/s but it was stable. But now you're saying your client connection is only ~3MB/s (25Mbps minus protocol overheads) so I'm not sure what more you're expecting when the router's upload is only 20Mbps (<2.5MB/s).
It was one of a tests. I also done one with two sources, but no progress. But in this test I was not 100% sure about the stability of 4G upload, since it was not stable and with help of @Tech9 I already got another idea.
That's why I'll do another test tomorrow with two stable sources, one with 20Mbit upload ad other with 30Mbit upload, so it should be over 5MB.
 

Seamus

New Around Here
I've done tests from my office and yes, I was looking way to narrow in first post...
Connection works till ISP provider limit...
Upload to VPN server around 2MB/s and download around 12MB/s (100Mbit) on location with good connection:
1648709749800.png


CPU was was at 38-39% at 12MB/s:
1648709784503.png


So I must find an option with higher UL speeds, if this is possible on location.

Thank you for support.

And one information about CPU usage - upper situation is with AES-128-GCM cipher

While with AES-128-CBC, the CPU usage is slightly higher - for around 4-5%:
1648710268762.png
 

sbsnb

Very Senior Member
Don't discount issues related to your office network. My employer deprioritizes all traffic that's not on a small handful of specific ports and caps the speed at 1 Mbps. If I want normal speeds on my VPN I have to assign it to one of the ports that isn't deprioritized, like 443.
 

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