AD DS 2003 2008 2012 memory consumption?

Question

RAM

You need to run a virtual machine, from the roles only ActiveDirectory, there are about 30 users. XP/7 clients, SSO authorization + some GPOs. Interested in comparing memory consumption in versions of
windows server 2003
windows server 2008 core
windows server 2012 core
Theoretically, 2003 should eat the least because x86 and the rest x64, but is it really so?

Answer 1

On a virtual machine, 256 MB is enough for everyone

Answer 2

What prevents you from asking Microsoft "Windows Server System Requirements"
From 512 M
So with 2 G it will be more than comfortable.
Are you considering AD emulation by Linux?