A 64-bit system architecture refers to a processor or operating system that processes data and memory addresses represented using 64 bits (8 bytes). A 64-bit processor can theoretically address up to 18.4 exabytes (2⁶⁴ bytes) of RAM, although practical limits are imposed by hardware and operating system design. The wider register size allows for more efficient handling of large integers, larger memory addressing, improved performance in some workloads, and enhanced security features such as address space layout randomization (ASLR). Most modern desktops, laptops, and servers now use 64-bit processors and operating systems.
