WinPE-x64 refers to the 64-bit version of WinPE, which is designed to run on x64-based systems. The x64 architecture is a 64-bit version of the x86 instruction set, used in many modern CPUs. WinPE-x64 provides support for 64-bit processors, allowing it to run on systems with more than 4 GB of RAM and take advantage of the increased processing power.