+ Memory Info

How It All Works


Since the days when computers used single dram chips, memory manufacturers have come up with different types and configurations of computer memory. From fast page mode (FPM) to extended data output (EDO) to SDRAM to double data rate (DDR) to RAMBUS, there are many different types of memory that have been used and currently being used with today. The most widely used type of memory right now is the DDR. DDR is basically an SDRAM type with twice the frequency. With this simple improvement, the computer industry embraced the change and became pretty much the preferred choice. Rambus, although superior in speed and throughput than DDR, never got the acceptance from the industry like DDR did. One reason for this is that, motherboard manufacturers didn't want to pay royalties to Rambus for implementing the technology on their products.


With the release of DDR2 in the mainstream market, OEM manufacturers are still testing the waters so to speak, on how the consumers will react to this highly touted replacement for the now aging DDR.


DDR2 provides twice the external bandwidth of DDR with the same internal frequency. Also, DDR2 addresses the insatiable requirement for lower power consumption on desktops and most especially for laptops. The 1.8V of DDR2 modules won't make much of a difference in battery life in portable devices since the memory system typically consumes only about 10% of the total power consumed by the PC. Still, something is better than nothing at all.


DDR2 has three different flavors from 400Mhz, 533Mhz and 667Mhz. Where DDR left of and where DDR2 takes over is somewhat blurred since both DDR and DDR2 has speed specification of 400Mhz and ~500Mhz. Although the pin count changed from 184pins to 240pins for the long DIMM, the pin count for the laptop modules stayed the same at 200pins.