Low performance on Back Office Catalog -> Categories

[Eman9]

Hello guys.

 

I have been working in a car parts store, and I'm adding a tone load of categories (Already have 6.000).

 

The front store and the back office works fine, just the Catalog->categories section is really slow to load. I'm having 6 up to 20 seconds loading per page. Average its around 9 seconds.

 

This happens in the following:

-when I'm navigating through the categories

-when I press the button "Add Category" 

-when I save a new category

 

However when I query the database through advanced parameters->Database takes less than 2 seconds, so I'm not sure if it's server side problem.

 

The time figures I'm using are not the ones showed by prestashop but by the browser extension. The prestashop figures are all the times much smaller.

 

I already searched a lot and tried everything I found out, increased webserver performance (RAM 3 gigas + SSD + Dualcore) but no success.

 

Does anyone have a clue how to fix or improve that?

Thanks