OpenVPN is a well-known VPN client for secure remote access or virtual private networking. If you use OpenVPN and experience a slow speed over its channel, you might be getting annoyed. This issue is very common for all OpenVPN users. While the general advice you can find on the Internet is to tweak the MTU (Maximum transmission unit) value and/or MSSFIX parameters, here is another trick you should try. It can help you significantly improve the bandwith. Here's what you should try.