“Start” function taking 8 seconds

When I save drafts, publish posts or work with other databases (e.g., Now Reading plugin), it takes a long time to process, for lack of a better term. This has occurred on every version of WordPress and with different themes.

Today I installed WP Tuner. I just saved something to the database and it took 8.669 seconds. Here’s what WP Tuner shows:

Index O
Marker Start
%Time 96
%DB Time 58
%DB Count 36
Time 8,301.6 msec
DB Time 2.2 msec
DB Count 4

All the plug-ins took only 0.1 msec each. The remaining time was used by these processes: init (1%), admin_init (1%), admin_head (2%) and admin_notices (1%).

Being wholly unfamiliar with this area, what would cause “Start” to take so long or what does it indicate?

Thanks