What is a characteristic of x64 CPU architecture?

A characteristic of x64 CPU architecture is its ability to support a 64-bit instruction set. This architecture allows for more memory addressability compared to 32-bit systems, enabling the CPU to utilize significantly larger amounts of RAM, theoretically up to 16 exabytes. This capacity is beneficial for running modern applications and operating systems that demand high performance and larger memory spaces.

In contrast, the other options do not accurately describe x64 architecture. The limitation to 1 GB of RAM pertains to older 32-bit architectures, which cannot address more than 4 GB effectively. The mention of supporting only a 32-bit instruction set is also inaccurate, as x64 CPUs can run both 32-bit and 64-bit instruction sets, thereby ensuring backward compatibility with older software. The requirement for at least two processors to operate does not apply to x64 architecture specifically; many systems, irrespective of architecture, can work with a single processor. Therefore, the defining feature of the x64 architecture is its support for a 64-bit instruction set, allowing for improved performance and resource utilization.