An external memory based FIFO (xFIFO) apparatus coupled to an external memory and a register bus is disclosed. The xFIFO apparatus includes an xFIFO engine, a wDMA engine, an rDMA engine, a first virtual FIFO, and a second virtual FIFO. The xFIFO engine receives a FIFO command from the register bus and generates a writing DMA command and a reading DMA command. The wDMA engine receives the writing DMA command from the xFIFO engine and forwards an incoming data to the external memory. The rDMA engine receives the reading DMA command from the xFIFO engine and pre-fetches a FIFO data from the external memory. The wDMA engine and the rDMA engine synchronize with each other via the first virtual FIFO and the second virtual FIFO.