I appreciate the replies. I just thought it was odd that since I had been turning this option on since the very first time it was introduced in SEP 11, I never had any slowdown issue what so ever, until the very latest version of SEP. The slowdown was much more than a few milliseconds. For instance, Gmail - instead of logging in and going to the mailbox in under a second, it would take a couple of minutes. Instead of instantly logging out, it wouldn't let you log out because it wouldn't go through. Facebook messages often wouldn't load at all - and if they did, would take minutes. And as I mentioned, when conducting a Speed Test, it wouldn't even allow "Upload" speed to be tested, because it would be stuck on "Connecting..."
But, it's OK. I'll just keep it OFF for now. Just wanted to let you guys know that the feature is definitely creating performance issues that were not present in any of the previous versions. Maybe it never worked in the previous versions, and now it's suddenly "working?" I don't know.
Anyway, thanks!
P.S. I have used ALL previous releases of SEP (from the very first version of 11), and never had this problem before. I even switched back from the 12.1 RU2 to 12.1 MP2 and the issue was not present - then went back to RU2 and it came back).