GT-AXE11000 OpenVPN vs Wireguard VPN client: Bandwidth troubles

[js42]

I have a Asus ROG GT-AXE11000 router running Merlin 388.2_2_rog firmware. I noticed a behavior with the Wireguard VPN client setup on the router with the stock firmware and had not found a good solution and thought of giving the Merlin firmware a try. The problem still persists. The situation is as follows:

I have several devices in the intranet that I route through a VPN tunnel from the router. These devices themselves, many only have a fast ethernet card and hence max out at about 90-100 mbps bandwidth. I also have a desktop linux machine that I independently use Wireguard VPN tunnel for best performance. My ISP (without VPN) clocks in typically at about 900 mbps download speed. My desktop linux machine routinely gets me about 820-840 mbps with Wireguard. I am fine with that overhead on VPN. Now for the problem:

When the router's VPN tunnel is using Wireguard, my desktop machine's max speed drops to roughly half ( ~400 mbps) even if there is no major usage from the devices in that tunnel - again, my desktop is outside this tunnel with its own independent VPN connection. If the router's VPN tunnel is using OpenVPN to the same VPN server, my desktop is able to maintain the full speed around 820 mbps. The issue is always consistently happening whenever I use Wireguard on the router.

When I asked the VPN provider, their advise was to look into the router.

Question:

Is this a problem with the wireguard implementation in the router or a setting that is somehow "reserving" roughly half my bandwidth?

Please help. If you need any further details, please let me know. Thanks.

 

[Syjeklye]

I have recently upgraded my internet and I am using the GT-AXE16000 router with the latest Merlin firmware as well.

If you read through the changelog you'll find this section on Wireguard:
"Note that enabling WireGuard will disable hardware
NAT acceleration due to compatibility reasons."

Changelog (current) | Asuswrt-Merlin

www.asuswrt-merlin.net

That is why you see the lower performance. I just set all this up and ran into this issue. I have the 5gb fiber and if my Wireguard is enabled on the router, it drops my download down to about 3.7gbps and my upload drops from about 5gbps to only 800 mbps.

I don't have a solution for it yet either. I might try OpenVPN again or set up a dedicated Wireguard server on my network.

 

[js42]

Thanks. It's at least good to know that I am not the only one experiencing this problem. If you or someone else figures out a solution/workaround, please let me know!

 

[Syjeklye]

Thanks. It's at least good to know that I am not the only one experiencing this problem. If you or someone else figures out a solution/workaround, please let me know!

I don't think there will be a work around since it's a hardware limitation. Unless they re-do the way Wireguard works (Doubtful).