3.0 significantly slower than previous versions?

Did you see this one? http://forum.codeigniter.com/thread-1579...#pid316310

Yes, i saw it.
But in system/libraries/Session/drivers/Session_database_driver.php line 94
CI will auto aborting if "pconnect" config set TRUE
Disable that lines and set pconnect TRUE will increase performance to ~30 milisecond loading.
(Why did they let us config while treat it like an error? LOL)

By the way, with CI 2.2.0 i can set pconnect TRUE, FALSE and whatever it is, page loading time always < 10 milisecond (my favorite framework, fast like hell  )

Yeah, well ... if you want to set pconnect to TRUE, don't use database sessions. It's all made that way for a reason.