Microsoft Offers Separate Feature Update Packages
For enterprise customers with System Center Configuration Manager or Windows Server Update Services, Microsoft offers a new option for Windows 10 functional updates that significantly reduces the size of the update packages. In the past, major feature updates, such as the Windows 10 1703 or 1709 versions, were offered in download packages that included both, the x64 and x86 versions. Now, the software company provides a separate package for the x64 version from Windows 10. According to Microsoft, these download packages are only around 2.6 GB instead of around 4.8 GB and are available for Windows versions 1703, 1709 and 1803; a pure x64 version for Windows 10 version 1809 is already announced.
However, companies using Windows 10 in the 32-bit version will still need to use the full packages.
Source: Microsoft