My drupal site is taking too long wait time, and it uses CPU + memory. My server setting is
16GB RAM, 8 processors. So it is good.
I am using Commerce Kickstart distribution have enabled 180 modules all are required cant disable a single module, I cant use caching coz content is mostly dynamic. My site loads in 8 second (most pages) in which wait time is only 6-7 seconds. Multiple hits takes CPU usage to 100%. I have checked reports with xhprof, top command on server, database tuning script, front page executes 4,52,600 functions, PDO commit taking 31% CPU, Database connections are not properly closed.
I have tried database tuniing module, database tuning script but nothing is working fine right now for me.
Cant use caching even default drupal views caching.
Please suggest some steps, any help will be a big big favor. Website i am building is dynamic so caching is prohibited.