In the multiple years I've worked with Game Maker: Studio... I had never known much about texture pages. I understand that you must put them onto as few pages as possible but I did not know a one simple thing. It is of the utmost importance.
DON'T CALL DIFFERENT TEXTURE PAGES BETWEEN DRAW CALLS.
My stupidity can be seen here: http://gmc.yoyogames.com/index.php?showtopic=678037
The point is that Project Explore is running like butter now. I've turned 50 texture swaps into about 20. I am making optimizations everywhere I possibly can at the moment.
The New Way To Render The Inventory
I Added 3D Objects! (Furniture)