DDR SDRAM (Double Data Rate Synchronous Dynamic Random Access Memory) is a memory IC which is often used in computers. As the name implies (DDR, Double Data Rate), this RAM has twice the bandwidth of SDRAM memory. In one heartbeat cycle (clock cycle) is able to transmit from two data(double pumped, dual-pumped, double transition), which is when the curve is high and the clock signal when the clock signal curve is falling. DDR SDRAM modules was first introduced and used for the PC in 2000.
DDR SDRAM is a type of DRAM 64 bits. Thus the maximum data transfer rate is 16 times the DDR SDRAM memory bus frequency (2 x 8 x frequency of the memory bus). Suppose the memory bus frequency is 100 MHz, the maximum data transfer rate is 1600 MB / s (1600 MB per second), which is obtained from the calculation:
2x8x100 = 1600 MB/s
Figures 2, stating the value of DDR (double pump), data transmission occurs twice per cycle rate.
Figures 8, said memory bus width in bytes (64 bits = 8 bytes).
100, states the frequency (clock speed) memory bus (100 MHz).
Please note that the use of technology DDR SDRAM DDR (Double Data Rate) only for the data transmission path, while the Address and Control signals are still using SDR technology (Single Data Rate).
Between DDR SDRAM with one another, in principle, there is no architectural difference, the only difference occurs at the speed / frequency of bus-only. For example, PC-2100 designed to run on bus frequency (clock) 133 MHz, while the PC-3200 is designed runs to the bus frequency (clock) 200 MHz. The higher the frequency of the memory bus, the faster transmission of data was done by the DDR SDRAM.
DDR SDRAM can usually be set to work faster than its standard bus frequency or work slower than its standard bus frequency. In practice, setting the DDR SDRAM that works at speeds exceeding standard bus frequency, referred to as overclocking. Meanwhile, when set to work at a slower speed than the bus frequency standard, called underclocking. Understanding overclocking and underclocking the DDR SDRAM is analogous to the notion of overclocking and underclocking the processor. Basically, overclocking is to increase the clock frequency, while underclocking is the reduction of the clock frequency.
DDR SDRAM is used for general desktop PC DIMM type which has 184 pins. The amount is more than the pin SDRAM DIMM type which also only has 168 pins. However, the pin number is lower than the DDR2 SDRAM has 240 pins. Thus, physically, DDR SDRAM and SDRAM are easily distinguished from the DDR2 SDRAM.
DDR SDRAM is used for different Desktop PC with DDR SDRAM used for laptop / notebook. DDR SDRAM for laptop computers called DDR SO-DIMM has 200 pins. DDR2 SO-DIMM also has 200 pins. DDR SDRAM is designed to operate at a voltage of 2.5 volts (compare with SDRAM is designed to operate at a voltage of 3.3 Volts). Especially for chips or modules standard DDR-400 (PC-3200) is designed to work at a voltage of 2.6 volts. It is clear that the DDR SDRAM is more energy efficient than SDRAM. Therefore, the DDR SDRAM is suitable for laptop computers because it can save more battery energy than SDRAM.
Compatibility DRAM attached to the motherboard is very dependent on the processor and chipset found on the motherboard. In this case, the chipset is very important role, because chipset that determine / set the type or types of memory what is appropriate or can be attached to the motherboard, and even set / determine the capacity and number of memory modules that can be paired. Now this is not a bit of the new chipsets that use a type of memory (DDR SDRAM) is configured dual channel has a bandwidth of two or four times the single channel memory.
- DRAM (Dynamic Random Access Memory)
- FPM DRAM (Fast Page Mode DRAM)
- EDO RAM (Extended Data Out RAM)
- SDRAM (Synchronous Dynamic Random Access Memory)
- RD RAM (Rambus Dynamic Random Access Memory)
- DDR2 SDRAM (Double Data Rate two Synchronous Dynamic Random Access Memory)
- DDR3 SDRAM (Double Data Rate three Synchronous Dynamic Random Access Memory)
- DDR4 SDRAM (Double Data Rate four Synchronous Dynamic Random Access Memory)
- SRAM (Static RAM)
- VRAM (Video Random Access Memory)
- SGRAM (Synchronous Graphics RAM)