DDR Memory Upgrades

DDR SDRAM – double data rate synchronous dynamic random access memory interface sometimes referred to as DDR1 SDRAM, is a class of memory integrated circuits used in desktop and laptop computers that been superseded by DDR2 SDRAM and later DDR3 SDRAM. None of the three are forward or backward compatible – DDR2 or DDR3 memory modules will not work in DDR equipped motherboards, and vice versa.

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DDR SDRAM’s interface allows higher transfer rates than SDR SDRAM via more strict control of electrical data timing and clock signals. Phase-locked loops and self-calibration have often been implemented to reach the required timing accuracy. Utilizing both the rising and falling edges to transfer data (double sampling) lowers the clock frequency giving it the advantage of reducing the signal integrity requirements on the circuit board that connects the controller and memory. “Double data rate” is so named because DDR SDRAM with a given clock frequency yields nearly twice the bandwidth of a single data rate (SDR) SDRAM operating at the same clock frequency, a direct result of double sampling. For example, with data being transferred 64 bits at a time, DDR SDRAM yields a transfer rate of (memory bus clock rate) × 2 (for dual rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Therefore with a bus frequency of 100 MHz, DDR SDRAM’s maximum transfer rate is 1600 MB/s.

Desktop Memory Installation

Laptop Memory Installation