Side-by-Side Comparison
RAM
DDR vs. DDR2
Comparing 2 standards across 5 specifications. 5 key differences identified.
Comparing:
DDR
DDR2
DDR SDRAM (sometimes called DDR1), finalized by JEDEC in 2000, was the first double-data-rate memory standard -- transferring data on both the rising and falling edge of the clock signal. It used a 184-pin DIMM for desktops and a 200-pin SO-DIMM for laptops, running at 2.5V.
DDR2, standardized by JEDEC in September 2003, doubled DDR's internal prefetch to 4 bits and dropped operating voltage to 1.8V. Its 240-pin DIMM introduced a new pin count, but its 200-pin SO-DIMM confusingly matches DDR1's pin count -- the two are still incompatible via a different notch position.
Specification Comparison Table
5 Parameters| Parameter / Spec | ||
|---|---|---|
|
JEDEC Standard
|
2000 (JESD79) | September 2003 |
|
DIMM Pins
|
184 | 240 |
|
SO-DIMM Pins
|
200 | 200 (same count as DDR1, different notch position -- not compatible) |
|
Nominal Operating Voltage
|
2.5 (2.6V for DDR-400) V | 1.8 V |
|
Data Rate Range
|
200–400 (DDR-200 to DDR-400) MT/s | 400–1066 (DDR2-400 to DDR2-1066) MT/s |