ovpn-dco VS ovpn-dco-win

We also back several OpenVPN related drivers, such as tap-windows6 driver, ovpn-dco-win driver, ovpn-dco linux kernel module. The tap-windows6 driver is the old Windows driver, which gives a pretty basic tun/tap interface. The DCO drivers are the next generation drivers, where more of the cryptographic operations are moved into the OS kernel instead of happening inside the OpenVPN Core components; which has the potential to improve the tunnel performance.

With Linux, there's lots of stuff going on in the OpenVPN community, in particular with a kernel module to accelerate the performance. The OpenVPN 3 Linux client already supports it and the coming OpenVPN 2.6 release (currently in development) will add support for both server and client mode with data channel offload (aka DCO).

Here is link number 1 - Previous text "DCO"

All that said, with the work being done in OpenVPN with the Data Channel Offload (DCO), it would probably be easier to get hardware support. The DCO implementations (ovpn-dco, ovpn-dco-win) offloads the data channel crypto operations to the virtual network driver, so the encryption/decryption/packet authentication happens entirely in the kernel space - which results in a noticeable performance boost. The tasks these DCO drivers does should be possible to more easily implement inside some dedicated hardware. But it won't be cheap.

There are work in progress on a OpenVPN kernel module, which will improve OpenVPN performance considerably: https://gitlab.com/openvpn/ovpn-dco

We also back several OpenVPN related drivers, such as tap-windows6 driver, ovpn-dco-win driver, ovpn-dco linux kernel module. The tap-windows6 driver is the old Windows driver, which gives a pretty basic tun/tap interface. The DCO drivers are the next generation drivers, where more of the cryptographic operations are moved into the OS kernel instead of happening inside the OpenVPN Core components; which has the potential to improve the tunnel performance.

My point is ... if the OpenVPN server is correctly configured, it can perform quite well compared against its competitors. If you're running Linux, the openvpn3-linux client also supports DCO (OpenVPN kernel data-channel off-loading) now. There is also work happening on a Windows driver as well. How much performance boost DCO gives against ProtonVPN is unclear, but against OpenVPN Cloud (which also has kernel acceleration on the server side) it can improve the performance if your network link to the OpenVPN Cloud servers is good enough. OpenVPN 2.6 will come with DCO support for both client and server side too.

All that said, with the work being done in OpenVPN with the Data Channel Offload (DCO), it would probably be easier to get hardware support. The DCO implementations (ovpn-dco, ovpn-dco-win) offloads the data channel crypto operations to the virtual network driver, so the encryption/decryption/packet authentication happens entirely in the kernel space - which results in a noticeable performance boost. The tasks these DCO drivers does should be possible to more easily implement inside some dedicated hardware. But it won't be cheap.