Large PDF's very slow

Lately, the projects I have been printing to pdf are very slow. They are slow to open, slow to scan through pages and basically do anything. Its not so bad on smaller projects (<50 pages), but on larger projects, performance seems to be suffering badly.

I am guessing this is more of an Adobe issue that an FDOT/Microstation issue, but since many of us here deal with printing our projects to pdf, I thought I would ask.

Has anyone else been experiencing this? Anyone found a solution?