Rhino Crashes starting rendering with Flamingo nxt

I am trying to make a poster size format rendition for a banner. I have done this before with similar settings but now even with smaller resolution (150dpi instead 300dpi) rhino either freezes, takes about a day for one pass or crash. I remove plants from the environment thinking that it will make the the progress quicker but it is still unbelievable slow. Any Ideas?

Moved to Flamingo category