Large Amount of Pages = Slow Backend?

Hello Forums,

I have a webpage in development. We are at 4,000 pages now, and not even close to being done. A problem I am seeing is that as we get more and more pages, the "Pages" screen, where it lists all the pages, becomes more and more slow. Also, the "Add a page" button may be slowing a little bit also. I am wondering if every time the "Pages" screen is displayed in the backend of WP, is it counting all the pages from the Database? I am wondering if there is any way to have it count only some, or cache the number somehow. Well, I will just ask it this way: is there any way to keep the speed of these backend screens fast?

At 4,000 pages, we have a slowdown. What will it be like at 40,000?

Anyone have any ideas, or experience with massive WP sites?