3.1 even with IDEFix can be a little tempremental about anything over the first 4GB not matter what the file system and i found that SFS at first can be a bit picky expecially when it comes to formatting. However usually at about the point when you've just torn out the last bit of hair and done something that shouldn't really have anything to do with it thats when it usually works. The only thing i can say is any partition after the first 4GB that is >4GB will have issues at first but once working should be fine.