I have read there isn’t a windows vista support for unity3d.
This means it’s impossible to use unity3d with windows vista ?
No, it’s not !
Am using Unity5 on Windows Vista machine, and aside from the bugs in the Engine, have had NO issues. Have used
the Engine from 4.5 to present on same machine.
You’re not going to get far in game development without having google-fu or the ability to look up an answer, from the product page to here: http://unity3d.com/unity/system-requirements
ie. windows xp and 7 are fine, but vista is unofficially supported so use at own risk! The best thing to do is download and try it out. You can also find stats on http://stats.unity3d.com
Does Windows 7 supports 16GB memory ?
if your running the 64bit version yes