I read a lot about many ways to improve drupal site performance optimization, but I did not find a clear indication of the top 10 most relevant modifiations for optimizing the performance of a complex site.
I currently am working to optimize a very complex site that has completely grown out of hand and needs serious modification because current page load speed is about 4 to 6 seconds for authenticated users. The website is mostly being used by authenticated users. The only access restriction is present through the Organic Groups module.
- 90 node types
- 140 select boxes checked on the admin/modules page
- 63 Vocabularies
- 240 views (excluding the additional views displays)
- 30 rules,
- 50 rules components
- 130 node panel variants
- 10,000 lines of css (excluding the omega base theme and modules style sheets)
What is the most important to start with, in general?