The problem is, that the frontend is slow, because all pages are loaded before they get hidden, etc.
Here you speak of frontend, but I think you mean backend as you posted in German forum
Questions,
if it is the backend, does this only occur in admin->pages?
And if you edit a page, when you go back to the pages list does the same slowness exist again?
If it is frontend, whay menu calls do you use?
What is happening with that number of pages is that the generation of the html takes time, the html output will be huge this allso affects the downloadspeed of that page.
If it is the backend, thngs can be done by paging the output of pages for example
If it is the frontend, I need to see the output of such a page to see where the problem lies
Remember that a small routine wich consumes just a fraction of a second might be huge when it is repeated 1300 times.
John