I have a scrolling ajax section on the home page that takes ~40 msec to load when I am not logged in, and 110-130msec when I am logged in. I have disabled all user tracking, and played with cookies vs sessions for authentication with no success.
Why is this? It is not what I would expect and I was wondering if there was anything else I could easily tweak? I am doing performance optimizations currently, and this is just a variable that keep annoying me. I understand for the most part that this has no effect for the typical users experience, it is just irksome to me as I am digging into which templates and configuration settings give me performance increases. (APC + CE_Cache have been by far the biggest btw) Disabling user tracking removed multiple db writes per page load, as did template hit tracking. Writes to the DB for every page view across multiple web servers was another bug speed increase.
My gut is telling me that user tracking being disabled is still doing the same amount of work, but is 100% correlation between being logged in on another browser tab or not.