Both the Pritunl server and client will need to encrypt/decrypt all network traffic sent over the VPN connection. If either the server or the client have a slow CPU the bandwidth will be significantly lower. The AES encryption cipher is used by default and a CPU with the AES-NI hardware acceleration will perform significantly better. A fast Intel CPU with AES-NI on both the client and server will be needed to achieve connection speeds exceeding 100mbps. If high bandwidth is needed for a large number of VPN clients concurrently a much more powerful CPU with AES-NI will be needed on the server.
Using smaller key sizes such as AES 128bit with SHA-1 in the server settings will significantly improve bandwidth but will make the encrypted traffic more vulnerable.
Updated over 2 years ago