Hi  @Semyon98 

1. The VPN speed is also limited by the VPN server/provider;

2. Not sure what traffic cost the CPU. Accourding to your topology, the router is not a VPN server/client, it's just doing the NAT.

The router has a special designed chip that can help CPU do NAT. So if there is no special usage, the router's CPU do not need to handle NAT and you will see like 1-2% usage. 

However if the traffic requires CPU to verify, for example if you enable access control, then this NAT chip won't work anymore and the data has to be handled by CPU. 

I'm thinking if you have configured this tp-link router as a VPN client? For ER605 v2, PPTP VPN Throughput Encrypted: 75.80 Mbps

Semyon98 wrote

Hello.

 

My ISP gives me 830 mbit/s of download and upload, but speedtest sometimes shows the speed even more. There is only one connected device to my router and it's hypervisor with several virtual servers. An Ubuntu Server 18.04 is installed on hypervisor. One virtual server is using my ISP's IP address, so the Internet speed on it is about 800-900 mbit/s, for other ones I've rent cheap VDS servers just for IP addresses and installed pptpd on all of them. The ping between my hypervisor and these cheap VDS servers is 5-7ms. So Internet on my home VDSes works like this:

 

(Home VDS) -> (VDS in Datacenter via PPTP) -> (Internet)

 

The problem is, when I'm trying to run Speedtest on one of my servers with my ISP's IP address, the speed is about 800-900 mbit/s and router's cpu load is literally 0-1%.

 

 

 

But when I'm trying to run Speedtest on one of my servers with rent VDS' IP address, the speed is about 80-100 mbit/s and router's cpu load is about 35-45%.

 

Why is this consuming my router's CPU so much and is there a way to get rid of this?

Hi  @Semyon98 

Have you checked your local server's Ethernet port speed? Could that be limited by 100Mbps?