Terminating SDRAM on opposite side of board
We need to know what RAM generation you are using? DDR 4/3/2/1?

For efficiency you should determine if you need termination before you even route the board. See this question: What types of signals should be considered to have a 50 Ω trace impedance? 

PS: There is a lot of free and good examples on how DDRx memory systems can be routed on the JEDEC website.