Open-world games cannot load the entire map into RAM simultaneously. RAGE utilizes a streaming engine that loads assets on demand. When a player enters a specific neighborhood, the engine prioritizes the loading of the relevant x64 archive sectors. The internal structure of the RPF file includes a lookup table (a file allocation table) that allows the engine to jump instantly to the byte offset of a specific texture without decompressing the entire archive.

Some popular tools for working with X64 RPF files include:

Modifying x64.rpf can trigger anti-cheat in GTA Online and may corrupt your game. Always work with a backup or use a mods folder. This write-up is for educational purposes only.