I'm a curious developer and VirtualBox user and I'd like to understand a little more about running 64 bit guests on 32 bit OSes. I hope I'm asking in the right place, if not, please advise me. I'd like to know the following:
1) I've read on many places (including the Manual) that there is some overhead by doing this, but I didn't find the causes of this overhead. Since it is done using VT-X (which I guess it gives an "isoloated" processor mode), I thought that no conversions and stuff like that would be needed. So, what are the (technical) reasons for this performance hit?
2) Based on it causes or experiments, does anyone have an estimative of how big (% or whatever) is this overhead?
3) Does this overhead also occur on Mac OS X Leopard, which is (correct me if I'm wrong) alleged to be able to run 64-bit processes?
4) If the answer to (3) is affirmative, do you think this overhead will also occur on Snow Leopard Mac OS X (which seems to have full 64 bit libraries and executables support)?
Thanks in advance, and sorry for doing so many questions on a single post, but they're all related.