These days it's pretty negligible, at least in my experience. If you every get to the point where the SSL handling CPU load is a problem, you're driving a TON

These days it's pretty negligible, at least in my experience. If you every get to the point where the SSL handling CPU load is a problem, you're driving a TON of traffic and hopefully can afford another box or two, or an F5 to off-load the SSL. I've been involved with some REALLY big sites, and SSL didn't really impact performance at all.