HTTP vs HTTPS performance

Question

Are there any major differences in performance between http and https? I seem to recall reading that HTTPS can be a fifth as fast as HTTP. Is this valid with the current g

Answer 1

A more important performance difference is that an HTTPS session is ketp open while the user is connected. An HTTP 'session' lasts only for a single item request.

It you are running a site with a large number of concurrent users, expect to buy a lot of memory.