Understanding DDR SDRAM and its Types
DDR SDRAM (Double Date Rate Synchronous Dynamic Random Access Memory) is one type of computer memory that has incredible speed in processing a data. People also often call it DDR RAM. This DDR RAM has the same architectural design as SDRAM, it's just using different clock signals to transfer data faster twice in the same amount of time. In computer systems science, the clock signal is the oscillation frequency used to coordinate the interaction between digital circuits, simply put, synchronization and communication. The design of this digital circuit to operate on clock signals that can respond to up or down signals.
DDR RAM transfers data on both sides up and down from the clodck signal. That's why DDR RAM is twice as fast as SDRAM. For the speed of RAM itself will work with the front of the bus (FSB) of a computer system. The FSB is a two-way channel data that transmits information from the central processing unit (CPU) to all existing components and embedded on the motherboard, including one RAM, BIOS chip, Hard Drive and PCI slot. Therefore, a computer system with a FSB of 133MHz runs DDR SDRAM which will basically perform like a 266MHz machine.
This DDR memory consists of 184-pin dual in-line memory modules (DIMMs) that only work well in motherboards designed according to the above conditions. DDR RAM comes in various speeds. DDR RAM will only run optimally if the motherboard supports.
DDR RAM is visually different from SDRAM where SDRAM is a 168-pin DIMM with double indentation at the bottom along the pin - only one off-center level, and the other offside. 184-pin DDR SDRAM has a single off-center notch. DDR RAM is usually made for 1GHz processor or faster. Debuts such as PC1600 DDR SDRAM and DDR SDRAM PC2100 coincide with certain FSB and CPU speeds required on the CPU. AMD and Intel use different schemes to demonstrate processor speed, and various technical and standard RAM designations can be confusing.
Types of DDR SDRAM
DDR (double data rate) 1st generation RAM is a memory that started using double clock cycle technology. This is different from SDR (single data rate) RAM which is only able to do single clock cycle. So DDR RAM is able to transfer data twice as fast.
DDR RAM has several types such as DDR-200 (has a memory clock of 100 MHz), DDR-266 (has a memory clock of 133 MHz), DDR-333 (has a memory clock of 166 MHz) and DDR-400 (has a memory clock of 200 MHz) . The transfer frequency DDR1 can generate is only between 200-400 MHz.
DDR RAM version 1 was developed from 1996 to 2000.
DDR2 RAM has twice the clock cycle. That is, his ability is twice as fast as DDR1. The memory clock is stretched from 100 MHz to 266 MHz. The DDR2 type has the standard names DDR2-400, DDR2-533, DDR2-667, DDR2-800 and DDR2-1066. And the transfer frequency between 400-1966 MHz.
While DDR3 RAM, in terms of memory clock is not much different from the DDR2 from 100 MHz to 266 MHz. The difference lies in the higher transfer frequency reaching 2133 MHz (maximum DDR2 only up to 1066 MHz) and the more efficient voltage is only 1.5v (DDR2 requires 1.8v and DDR 1 with 2.5 / 2.6v).
In Computers, DDR4 SDRAM, an abbreviation for Double Date Random Access Memory type, is a type of dynamic random-access memory (DRAM) with high bandwidth interfaces expected to be released to the market in 2012. This is one of several variants of DRAM that has been in use since the early 1970s  and is not compatible with all previous types of random access memory (RAM) due to different signal voltages, physical interfaces and other factors.
DDR4 memory is claimed as the latest generation of memory that has a rate transfer rate 2133 - 4266 MT / second where we know now is still DDR3 technology and it with a speed of 800MT / second.
For you minimal motherboard users with intel chipset G41 and DDR3 ram you must have felt the speed of 800Mt / second range. Then what about the upcoming DDR 4 which can actually be 4X higher than DDR3, coupled with a very low VOLTAGE of 1.05 - 1.2 V for DDR4 and 1.2 - 1.5 V for ddr3.