您搜索了: 可以基于处理器频率将它转换为秒数 (简体中文 - 英语)

一般情况下，总系统启动时间可以从处理器上的 rdtsc 寄存器获得（时间戳计数器）。该寄存器在完全关闭电源的情况下（或 s5 状态）设置为 0。其数值以时钟节拍为单位，可以基于处理器频率将它转换为秒数。
generally the total system boot time can be obtained from the rdtsc register on the possessor (time stamp counter). this register is set to 0 at complete power off (or s5 state). the value held is in clock-ticks which can be translated into seconds based on the processor frequency.

英特尔® 处理器频率 id 实用程序
intel® processor frequency id utility