I have an issue whereby my site is in the 12-13 seconds bracket in WMT site performance.
This is obviously a concern but i cant understand why it is slow, it loads fine for me, WMT bot crawl data suggests the same, and so do many people i have asked to test it from around the world.
The only thing i can find is i run a banner rotation script, that refreshes a banner every 60 seconds, so if you load a page and stay there for 30 mins, that banner will load many times over.
Could this be causing the issue? Technically the pages never finish loading, as the banner keeps going, indefinitely.
Would having the banners load from another domain fix this do you think?