The work of the system needs a unified rhythm, just like people's work and life, they work and rest according to certain time rules, and computers also need such a clock. The "timely clock" mentioned by the landlord is the necessary "clock" for the system to work, which is generated by the timely crystal oscillator and the oscillating integrated circuit for the system to use. This crystal oscillator is 32768Hz, which means 32.768KHz, not 32.768MHz. The time we usually see in the computer is generated by its frequency division. In addition, there is a crystal oscillator with the frequency of 14.3 18MHz, which is frequency-doubled by the frequency doubling circuit to provide the frequency needed for CPU external frequency PCI bus, RAM and other work. The two crystal oscillators mentioned above are necessary for the motherboard. Depending on the motherboard design, there will be other crystal oscillators, such as integrated network card, integrated sound card and modem, which all need corresponding crystal oscillators, but they are not necessary for the motherboard. In other words, if the motherboard does not integrate these functions, these crystals are not needed.