A server system is described. The server system comprises first motherboard having first processor module coupled to first memory module, second motherboard having second processor module coupled to second memory module, first back plate having first PCIE switch chip coupled to second PCIE switch chip via PCIE transmission channel. The first processor module is coupled to the first PCIE switch chip and the second processor module is coupled to the second PCIE switch chip. The first processor module converts the memory data of the first memory module into PCIE packet data to be transmitted to the second processor module by first PCIE switch chip and second PCIE switch chip. The second processor module converts the received PCIE packet data into memory data of second memory module for synchronizing the memory data of first motherboard and the second motherboard.