Is CS6 any more likely than CS5 to work in such a case?
Well the system requirements for CS5 show:
Mac OS X v10.5.7 or v10.6
Microsoft® Windows® XP with Service Pack 3; Windows Vista® Home Premium, Business, Ultimate, or Enterprise with Service Pack 1 (Service Pack 2 recommended); or Windows 7
Mac OS X v.10.7 (64-bit) or v.10.8 (64 bit)
Microsoft® Windows® 7 with Service Pack 1 or Windows 8 with Service Pack 1
So yes, there's a difference depending on what OS you have and wish to stick with.