I've been fighting some random IOExceptiosn over SSL which we believe to be SSL handshake issues when dealing with a lot of connections at once.
I read that Session resumption might help with this.
Googling I found some information on adding a registry key and using some power shell commands to enable it on Windows and IIS
using https://ssllabs.com to test it still shows disabled so I'm not sure what I'm doing wrong or even if this is the correct approach to resolving the issues.