What's the difference between DDR2 and DDR2 SD RAM?

Question

I have a Dell laptop and want to increase its memory. When checking its configuration, the RAM details was shown as DDR2 SD RAM. However some sites also show it as DDR2 RAM.

Is there any particular difference between DDR2 SD RAM and DDR2 RAM?

Answer 1

All DDR ram is SD ram. DDR stands for Double data rate - since All SD ram varients are synchronised with the clock speed of the system, The interface uses double pumping (transferring data on both the rising and falling edges of the clock signal) to lower the clock frequency and DDR SDRAM with a certain clock frequency achieves nearly twice the bandwidth of a single data rate (SDR) SDRAM running at the same clock frequency, due to this double pumping.

With non SD ram, well, its asynchronous, and there's no relationship between clockspeed and the ram's transfer speed, and as such there's nothing to be double of.

Very heavily referenced from the wiki entries on SD and DDR ram

Answer 2

No, since "DDR2" is short for "DDR2 SDRAM".