Electronic Software Download (ESD), a highly compressed format used to reduce the overall ISO file size.
1 GHz or faster with support for PAE, NX, and SSE2. RAM: 1 GB (x86) or 2 GB (x64). Storage: At least 16 GB (x86) or 20 GB (x64) free space. windows-8-1-aio-20in1-x86-x64-oem-esd-april-2020
Based on standard Windows 8.1 specifications for these AIO builds: Electronic Software Download (ESD)
The "20-in-1" designation refers to the variety of Windows 8.1 versions included within a single installer. While specific lists vary by uploader, these typically include: Windows 8.1 Home, Pro, and Enterprise. these typically include: Windows 8.1 Home