Ddr ii Ram
Product description
DDR-2 SDRAM supersedes DDR-1 SDRAM specifications. Like DDR-1 SDRAM, it also transfers data on both rising and falling edges of bus clock signal, but also, it runs the internal clock at half the speed of the data bus. Thus, DDR2 memory operates almost at twice the external data bus clock rate as DDR may provide twice the bandwidth with the same latency.
DDR2 SDRAM modules are internally configured 4 or 8-bank DDR2 SDRAM devices. DDR2 SDRAM modules use DDR architecture to achieve high-speed operation. DDR2 architecture is basically 4n-prefetch architecture. DDR2 is designed to transfer two data words per clock cycle at the I/O pins. It consumes less power which is 1.8v as compared to its predecessor DDR-1 SDRAM which requires 2.5v. Long-DIMM (or Desktop RAM) comprises of 240 connector pins, whereas SO-DIMM (Laptop RAM) comprises of 200 connector pins. It typically has data transfer rates of PC2-3200 (400MT/s), PC2-4200 (5300MT/s), PC2-5300 (667MT/s), PC2-6400 (800MT/s), or PC2-8500 (1066MT/s). PC2-8500 (1066MT/s) is usually possible with certain Processors and/or over-clocking, which should be supported by Processor, Motherboard & RAM at tandem.
Ddr iii Ram
Product description
DDR-3 SDRAM or Double Data Rate type Three Synchronous Dynamic Random Access Memory is a successor to DDR & DDR2. As compared to DDR2 SDRAM, it has ability to transfer data at double rate; i.e., eight times the speed of its internal memory arrays; thus enabling higher bandwidth (peak data rates). It has two transfers per cycle of a quadrupled clock signal; that enables it to achieve a transfer rate of up to 64 times the memory clock speed.
DDR3 SDRAM modules use DDR architecture to achieve high-speed operation. DDR3 architecture is basically an 8n-prefetch architecture which transfers two data words per clock cycle at the input-output pins. Initially it was launched with 1.5v DDR3 DRAM; later DDR3 DRAM works at 1.35v. 1.35v is usually compatible with all 1.5v platforms. Long-DIMM (or Desktop RAM) comprises of 240 connector pins, whereas SO-DIMM (Laptop RAM) comprises of 204 connector pins. Long DIMM of both DDR2 and DDR3 has 240 pins, but they can easily be identified as their notch location of DDR3 is nearer to pin 1 as opposed to DDR2 Long-DIMM. It typically has data transfer rates of PC3-6400 (800MT/s), PC3-8500 (1066MT/s), PC3-10600 (1333MT/s), PC3-12800 (1600MT/s), or PC3-14900 (1866MT/s).
Ddr iv Ram
Product description
We're starting to see a fair number of DDR4 memory options on the market, but DDR3 is still, by far, the go-to RAM. DDR4 is currently limited to Intel's X99 platform and Extreme processors, which are more expensive, and not much better for gaming, than the Core i5s and i7s we're accustomed to. DDR4 is still much more expensive than DDR3, but it also hits higher clock speeds. The question, then: how different is DDR4 from its predecessor, exactly? The folks over at AnandTech have gone to great lengths to answer that.
First off, DDR4 operates at a lower voltage than DDR3. DDR4 runs at 1.2 volts, down from 1.5. It doesn't sound like much, and it's really not for your typical home PC. Most Haswell-E desktop systems (where you'll most often see DDR4 in use) will operate somewhere in the 300W to 1200W range. The voltage difference for those numbers might account for a 15W savings over DDR3—not a lot for a home user. But for server farms and other large-scale computer architectures, where you could have hundreds of systems running thousands of DDR4 modules, that 15W difference adds up. Another big difference between DDR3 and DDR4 is speed. DDR3 specifications started at 800 MT/s (or Millions of Transfers per second) and some went as high as 2133. DDR4, meanwhile, starts at 2133 MHz. The increased speed means an overall increase in bandwidth.
This unfortunately comes with an increase in latency as well, but the increased clock speed makes for quicker transfers while maintaining an overall latency comparable to DDR2 and DDR3. DDR3-1600 operated at a latency of CL11, which took 13.75 nanoseconds to initiate a read. DDR4-2133 sits at CL15 and performed a read at 14.06 nanoseconds—only a 2% increase.