R2 introduces a new feature for Group Policy called Policy Caching. Basically, when this setting is enabled, the client will download the policies from a domain controller and store them locally.
So, what's the benefit?
According to Darren Mar-Elia, not a lot.
Per Understanding Group Policy Caching in Windows 8.1and More on Group Policy Caching in Windows 8.1, Darren suggests that while it does improve logon processing performance, it only does it in certain situations. Even though the name kind of suggests it, it "DOES NOT work to apply Group Policy when a machine is off the network or not in contact with a domain controller."
Group Policy Caching is not enabled by default, so if you want to utilize the feature, you'll need to enable it. To turn it on, open the Group Policy Management Console and navigate to:
Computer Configuration\Policies\Administrative Templates\System\Group Policy
Under the Group Policy branch locate Enable Group Policy Caching For Servers and Enabled it.