Hi,
Thanks for your post.
Windows Server 2012 is compatible with Windows 7.
But BranchCache in Windows Server 2012 and Windows 8 provides substantial performance, manageability, scalability, and availability improvements. And there are some group policy only applied to client computers that are running Windows 8 not Windows 7.
So i would suggest you may choose client computers that running Windows 8.
More detail information, please refer to:
http://technet.microsoft.com/en-us/library/jj127252.aspx
Regards.
Vivian Wang