I'm currently using COPSSH to tunnel various connections to a remote Windows box and connecting using plink.exe from the PUTTY suite. After connecting directly, I've come to realise that the quality of connection using this setup is appalling. Tunnelled connections appear to get slower and slower. Can anyone recommend secure tunnel software that is more performant than my current setup?
I've used both stunnel, and the putty family of tools (plink, putty), and I've only rarely found performance issues. I would imagine your slowness comes from poor network connection, or performance issues on either end of the pipe.
A UDP-based protocol will be more asynchronous than serializing over a tcp stream.
This should give OpenVPN better performance than OpenSSH on a lossy or high-latency network.
I find that plink.exe has much higher latency than Cygwin's ssh on windows. The difference is quite noticeable when using Synergy to share a keyboard and mouse.