Which factor is crucial for hardware compatibility with Windows 11?

The important factor for hardware compatibility with Windows 11 is TPM 2.0 compatibility. Trusted Platform Module (TPM) is a hardware-based security feature that helps protect sensitive data by allowing hardware-based security functions. Windows 11 requires a specific version of TPM, known as TPM 2.0, to enhance security and ensure that only trusted firmware and operating systems can boot. This requirement helps to guard against attacks that compromise the operating system's integrity.

While system memory size, storage size (whether HDD or SSD), and the version of Windows currently running are all elements to consider when assessing a system's capability to run Windows 11 or perform effectively, they do not directly determine the OS's compatibility as TPM 2.0 does. The presence of TPM 2.0 is pivotal for meeting Microsoft's minimum security requirements, making it a cornerstone for compatibility with Windows 11.