I have a small YII driven app that is using EXTJS 4.1 as GUI. It has some grids. The job here is to optimize the complete environment with apache-php-mysql and the app itselfes. There are a lot of small Issues that will decrease the speed of this site.
It needs to find best options to run the app with more speed. Test Environment is online - if you are interested I can give you access do first tests.
Here a list what Pagespeed has found for optimizing:
Reduce blocking resources (2)
Inline Small CSS
Minimize payload (6)
Serve resources from a consistent URL
Combine images into CSS sprites
Minimize delay in page load (1)
Avoid CSS @import
Leverage browser caching