Virtual Desktop Infrastructure (VDI)
Users will enjoy a rich desktop experience and the ability to play 3D graphics, use USB peripherals and use touch-enabled devices across any type of network (LAN or WAN) for VDI scenarios, thanks to enhancements in Microsoft RemoteFX and Windows Server 2012.

Start Screen Control
IT departments can now control the layout of the Start screen on company-issued devices to ensure key apps are easily accessible. IT departments can also prevent users from customizing their Start screen to ensure consistency across individual workgroups or the entire company.

AppLocker
T organizations can create a more secure environment by restricting the files and apps that users or groups can run on a PC, increasing the security of the device and the data it holds.

DirectAccess
Users can seamlessly access resources inside a corporate network remotely without having to launch a separate VPN. Also, IT administrators can keep remote users' PCs up-to-date by applying the latest policies and software updates.

Windows Enterprise Side-Loading
Internal Windows apps can be side-loaded on domain-joined PCs and tablets running Windows 8.1 Enterprise.

BranchCache
Employees in branch offices no longer need to download content multiple times across their Wide Area Network (WAN) as BranchCache caches files, websites and other content from central servers locally on hosted cache servers or PCs.


X64 Information:
MICROSOFT.WINDOWS.8.1.ENTERPRISE.RTM.X64.WITH.ROLLUP-1.ENGLISH.DVD-WZT
RELEASE DATE: 10/17/2013
RTM BUILD: 6.3.9600.16384.WINBLUE_RTM.130821-1623
ROLLUP UPDATE BUILD: 9600.16404.WINBLUE_GDR.130913-2141
FILE: en_windows_8_1_enterprise_x64_dvd_2971902.iso
SIZE: 3,853,993,984 byte
SHA-1: AE792B2EF982DAC7391224B624EAB8D6340D78AB
MD5: 8E194185FCCE4EA737F274EE9005DDF0
CRC: 8C56C9E2

X86 Information:
MICROSOFT.WINDOWS.8.1.ENTERPRISE.RTM.X86.WITH.ROLLUP-1.ENGLISH.DVD-WZT
RELEASE DATE: 10/17/2013
RTM BUILD: 6.3.9600.16384.WINBLUE_RTM.130821-1623
ROLLUP UPDATE BUILD: 9600.16404.WINBLUE_GDR.130913-2141
FILE: en_windows_8_1_enterprise_x86_dvd_2972289.iso
SIZE: 2,902,501,376 byte
SHA-1: 5EFB981C94E1223C85F3BB504D04E0642A85C1D4
MD5: BF620A67B5DDA1E18E9CE17D25711201
CRC: 13F1ACB4

NOTE: this is original MSDN image.
This ISO image included update rollup package
Windows 8.1 and Windows Server 2012 R2 General Availability Update Rollup
http://support.microsoft.com/kb/2883200/