Look for file sizes exactly 3.2 GB (x86) or 4.1 GB (x64) . Any ISO significantly smaller is likely a counterfeit, a stripped version (RIP), or malware disguised as an ISO. Also, check the file date—ISOs from 2013-2015 are often original RTM builds.
Microsoft maintains an archive portal for older operating systems. You can download the Windows 8.1 Disc Image (ISO) directly from the official Microsoft website. Navigate to the Microsoft Software Download page. Select the Windows 8.1 edition. Choose your product language. Select either the 32-bit or 64-bit download. 2. Using Internet Archive (With Caution) Index Of Windows 8.1 Iso
1 gigahertz (GHz) or faster with support for PAE, NX, and SSE2. Look for file sizes exactly 3