However, if you look at the obove mentioned spec's of my system, I should have enough hardware for running the 707 cabin
Sorry, I somehow missed your computer specs.

You should definitely have enough "grunt" to run the 707 easily. It runs fine with the cabin on mine, but does require an aircraft reload if I get the problem. And that is the thing for me, it doesn't happen all the time, but I can get rid of it if it does.

Mark