All DMD I/F signals should be terminated at the source with a 20-Ω series resistor.
MEM_CLK and MEM_CLKZ should be terminated with an external 100-Ω differential resistor across the two signals as close to the DRAM as possible. All other DDR2 control and data signals should be pulled to VTT(0.9 V) with a 56-Ω resistor as close to the DRAM as possible.