Windows 7 compressed ISO around 900 MB typically involves using unofficial "Lite" or "Super Lite" editions. Standard official Windows 7 ISOs are much larger—approximately 2.34 GB for 32-bit 3.10 GB for 64-bit Microsoft Community Hub Highly Compressed & "Lite" ISO Options
Because the OS is so lean, the hardware requirements are significantly lower than the official Microsoft specs: 1GHz (Single-core is sufficient). RAM: 512MB (Though 1GB is recommended for browser use). Disk Space: Approximately 3GB to 4GB of installed space. Essential Risks and Safety Tips
Some uploaders take a standard 3 GB+ Windows 7 ISO and use high-ratio compression algorithms (like .7z or .kgb ) to pack the file down to a tiny size for easier downloading.