Is the DDR2 series RAM better?

Answer 1

The advantage of DDR2 over DDR SDRAM is the ability for much higher clock speeds, due to design improvements. With a clock frequency of 100 MHz, "SDR-SDRAM" transfers data on every rising edge of the clock pulse, thus achieving an effective 100 MHz data transfer rate. Unlike SDR, both DDR and DDR2 are double pumped; they transfer data on the rising and falling edges of the clock, at points of 0.0 V and 2.5 V (1.8 V for DDR2), achieving an effective rate of 200 MHz (and a theoretical bandwidth of 1.6 GB/s) with the same clock frequency. DDR2's clock frequency is further boosted by electrical interface improvements, on-die termination, prefetch buffers and off-chip drivers. However, latency is greatly increased as a trade-off. The DDR2 prefetch buffer is 4 bits wide, whereas it's 2 bits wide for DDR and 8 bits wide for DDR3.

Power savings are achieved primarily due to an improved manufacturing process, resulting in a drop in operating voltage (1.8 V compared to DDR's 2.5 V). The lower memory clock frequency could also help — DDR2 can use a real clock frequency 1/2 that of SDRAM whilst maintaining the same bandwidth.

Answer 2

Better than what?

If you are comparing to plain DDR, it is faster overall. It's not the most efficient form of memory out there, but every little bit helps.

Search on Wikipedia or Google if you really need more info.

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Does it annoy anyone else when peeps copy/paste info from Wikipedia (hint, hint to next post below). Just post the link...