[stunnel-users] performance issue

Hello list. I like to use stunnel to secure my vnc connection. Everything is fine, the connection can be made. The problem is that it is getting so slow that I can't use it. The time difference in displaying the remote screen is really huge. Is this a known issue or is it my fault by using a wrong configuration? My stunnel server is on winxpsp2 and the client is on suse 10. Thanks for your help. Stefan