Speed drop with VPN Server enabled on RT-AX82u

[oleksandr.belei]

I'm using the Asus RT-AX82u on the stock firmware version 3.0.0.4.388_24231. My internet provider offers a speed of 1 Gbps. However, in reality, speed tests show around 800/900 Mbps. Whenever I activate one of the VPN servers on the router (Wireguard, OpenVPN, or IPSec), the connection speed drops to 230/80 Mbps. It's worth noting that no clients are connected to the VPN server at this time. The only VPN protocol without issues seems to be PPTP.

I've tried disabling various services such as AiProtection, QoS, Firewall, Port Forwarding, Traffic Analyzer, but it didn't help.

Has anyone else experienced similar issues with this model or a model with similar specifications?

 

[Adooni]

it is not issue it is normal - if you want to have VPN 1Gbit you need to use miniPC with strong CPU like i5, Xeon, i3 N305 etc. With wireguard depend at settings you will get a better results than OpenVPN
results for similar better router are here https://www.snbforums.com/threads/a...-with-nordvpn-or-any-other-vpn-service.68248/

router Asus RT-N16 (from 2009) have 1Gbit LAN/WAN ports but when you set OpenVPN on it you will get 5-10Mbit speed - a lot router OEMs do not tell whole truth

microtik for example is presenting results like here https://mikrotik.com/product/rb5009ug_s_in#fndtn-testresults

 

[ColinTaylor]

it is not issue it is normal - if you want to have VPN 1Gbit you need to use miniPC with strong CPU like i5, Xeon, i3 N305 etc. With wireguard depend at settings you will get a better results than OpenVPN
results for similar better router are here https://www.snbforums.com/threads/a...-with-nordvpn-or-any-other-vpn-service.68248/

router Asus RT-N16 have 1Gbit LAN/WAN ports but when you set OpenVPN on it you will get 5-10Mbit speed

He's talking about the router's VPN server, not the VPN client.

 

[oleksandr.belei]

it is not issue it is normal - if you want to have VPN 1Gbit you need to use miniPC with strong CPU like i5, Xeon, i3 N305 etc. With wireguard depend at settings you will get a better results than OpenVPN
results for similar better router are here https://www.snbforums.com/threads/a...-with-nordvpn-or-any-other-vpn-service.68248/

router Asus RT-N16 (from 2009) have 1Gbit LAN/WAN ports but when you set OpenVPN on it you will get 5-10Mbit speed - a lot router OEMs do not tell whole truth

microtik for example is presenting results like here https://mikrotik.com/product/rb5009ug_s_in#fndtn-testresults

I understand that some speed reduction is inevitable when connected via VPN. The problem is a drop in local speed when the VPN server is enabled on the router (no VPN client is connected).

 

[ColinTaylor]

I understand that some speed reduction is inevitable when connected via VPN. The problem is a drop in local speed when the VPN server is enabled on the router (no VPN client is connected).

There is a known limitation (in other models - I don't know about the RT-AX82U) when enabling WireGuard in that is disables the router's global hardware acceleration. That can result in the sorts of speed that you're seeing. Apparently Asus have a workaround for that but I don't know whether it's been implemented in your router's firmware yet. I don't know if the same problem would effect the IPSec server. However, enabling just the OpenVPN server should not effect the local speed, unless there's some other sort of limitation that's specific to your model.

 

[Deetlemore]

Piggybacking on what ColinTaylor mentioned, HW acceleration may not be enabled. Tech9 made a list of features that will disable HW acceleration on the AX82U: I dont have Nat Acceleration (ASUS RT-AX82U)

I don't think OpenVPN should be one of those either. You can check that HW acceleration is still enabled in Tools > Sysinfo. Alternatively, SSH into the router and use:

nvram get runner_disable
nvram get fc_disable

They should both return 0 if HW acceleration is enabled. Though I'm not certain that your router uses those exact types of HW accel, someone here may know the correct commands to check if those don't work.

 

[oleksandr.belei]

Piggybacking on what ColinTaylor mentioned, HW acceleration may not be enabled. Tech9 made a list of features that will disable HW acceleration on the AX82U: I dont have Nat Acceleration (ASUS RT-AX82U)

I don't think OpenVPN should be one of those either. You can check that HW acceleration is still enabled in Tools > Sysinfo. Alternatively, SSH into the router and use:

nvram get runner_disable
nvram get fc_disable

They should both return 0 if HW acceleration is enabled. Though I'm not certain that your router uses those exact types of HW accel, someone here may know the correct commands to check if those don't work.

If the value of nvram is to be believed, HW is enabled. Both commands outputs 0.

 

[oleksandr.belei]

Output of the fc status command

        Flow Timer Interval = 10000 millisecs
        Pkt-HW Activate Deferral rate = 1
        Pkt-HW Idle Deactivate = 0
        Pkt-SW Activate Deferral count = 0
        Flow Low Pkt Rate = 10
        Acceleration Mode: <L2 & L3>
        MCast Learning <Disabled>
        MCast Acceleration IPv4<Enabled> IPv6<Enabled>
        IPv6 Learning <Enabled>
        GRE Learning <Enabled>
        4o6 Fragmentation <Enabled>
        TCP Ack Prioritization <Enabled>
        HW Acceleration <Enabled>
        Notify Processing Mode <Hybrid>
        OVS Flow Learning <Disabled>
        Flow Learning Enabled : Max<16383>, Active<30>, Cummulative [ 283 - 253 ]