We have a very simple farm with one WFE and one db server. My boss is concerned that the use of HTTPS on our internal network could have negative perceived performance to our remote sites such as New Zealand where we have a very slow link between the two.
In your experience will using HTTPS in this sort of small farm situation impact performance?
Some good responses to a similar post here - HTTP vs HTTPS Performance. (There is some overhead due to the extra handshaking with SSL).
SSL will impact the performance a little for each request due to the extra HTTP negotiation and request/response encryption.
However, having said that, it wont have any perceivable effect on your New Zealand users any more than it would your users right next to the server. Latency is your problem there, and SSL will add mostly CPU load to your server.
This is because of periodical revocation certification checks on your server. Frequently web server is unable to make outgoing internet connections and timeouts at making such checks, than it processes a request. May be, that is your case? More information you can read in the article: https://docs.microsoft.com/en-us/sharepoint/troubleshoot/sites/site-slowness-because-of-sts-certificate-crl-checking
