Don't get the DDR board. Tt uses DDR memory, but only a 64 bit bus. All the other cards use SDR memory and a 128 bus. The larger bussed normal sdram is faster than the ddr ram.
btw some1 correct me if i'm worng on any of this.
Also one would assume that the ddr would be cheaper. Altho it's moree expencive ram, they only have to trace 1/2 of the bus and there for, save money.