After Microsoft Windows systems have used the Time Stamp Counter (TSC) as the preferred choice for high-precision timing for over a decade, the Linux kernel has now officially made TSC a mandatory requirement for x86 processors. This move removes the remaining configuration logic, making it impossible to build the x86 kernel without TSC support, marking the end of Linux's decades-long support for extremely old x86 hardware. TSC is a special 64-bit register that has existed since the Intel Pentium era, capable of measuring time with extremely high precision and reading at speeds far exceeding other platform-level timers. Today, all modern Intel and AMD processors are equipped with 64-bit TSC. With the gradual removal of support for older processors, there is no longer a need to retain the relevant compatibility code. This change does not make Linux suddenly reliant on features absent from modern PCs; rather, it removes code that was previously used to maintain compatibility with old hardware.