Main-board without restriction on memory frequency and control method thereof

A control method of a main-board, wherein the main-board comprises a CPU (Central Processing Unit), a clock-rate control-signal generating module and a chipset, and the chipset has a phase-locked circuit, a CPU-bus circuit and a memory-bus circuit, the method comprising:

• transmitting original ratio information from the CPU to the clock-rate control-signal generating module such that the clock-rate control-signal generating module generates a clock-rate control signal;
• transmitting the clock-rate control signal to the phase-locked circuit to enable the phase-locked circuit to set a transmission frequency ratio of an information-transmitting frequency of the CPU-bus circuit to an information-transmitting frequency of the memory-bus circuit according to the clock-rate control signal;
• generating clock-rate information and transmitting the clock-rate information to the clock-rate control-signal generating module to enable the clock-rate control-signal generating module to generate another clock-rate control signal according to the clock-rate information;
• and
• transmitting the another clock-rate control signal to the phase-locked circuit to enable the phase-locked circuit to reset the transmission frequency ratio of the information-transmitting frequency of the CPU-bus circuit to the information-transmitting frequency of the memory-bus circuit according to the another clock-rate control signal.