DDR

The basic principle .memoria ddr4

DDR 400MHz that 400MHz refers to the memory bandwidth, is a converted value of the operating frequency.
The DDR 400MHz memory runs at a clock frequency of 200MHz. DDR can access data twice per clock cycle, so it is equivalent to running at a clock frequency of 400MHz (200MHz x 2).
The same algorithm, DDR2 533 memory, running frequency of 133MHz, each clock cycle can access four times of data, equivalent to 533MHz (133MHz×4).
Of course, the higher the number, the higher the frequency, the faster the memory must be.
DDR3, 4 memory has matured, several times faster than DDR2, DDR3 is currently used by mainstream motherboards, and DDR4 positioning is still in the mainstream above.

Current situation of the development of memoria ddr4

The standard specification for DDR4 memory is almost complete, and Samsung and Hynix have already completed their samples. However, DDR3 is still in its heyday, so it is not expected to arrive in a hurry.
The latest news is that DDR4 memory will first hit servers in 2014, and then the desktop in about a year and a half.
Haswell-ex, Intel's next generation enterprise server platform, will be the first to integrate DDR4 memory controllers.
Haswell-ex is part of the same family as Haswell that we've always envisioned, targeting large enterprise domains such as data centers with up to 16 cores, 64 cores for four routes.
DDR4 memory not only provides a significant increase in frequency (up to 4266MHz), but also features low voltage of 1.2V, better peer-to-peer protection, and error recovery. These large-scale applications in servers and enterprise centers will see immediate benefits.
As for the desktop, both 22nmHaswell and 14nm broadwell will use the same LGA1150 package interface, and memory controllers will naturally be limited to DDR3. DDR4 support is likely to wait until "Skylake", a new architecture for 14nm technology, in 2015.
AMD's 2016 cpus are compatible with DDR4 memory and will be used in the next generation of AM4 interfaces, namely Ryzen5 and above and A9 and above.
This pace is not fast, market research agencies have previously believed that DDR4 memory should be basically available by 2015.

upgrading too quickly is not a good thing, everyone can enjoy cheap DDR3 more secure.hard drives

And if you're worried that Haswell and Broadwell are going to lose out on memory performance, don't worry. A DDR3 is sure to become more and more common, with new features such as ultra-low latency internal memory controllers, flush capabilities, floating point peak emittance, FMA arithmetic, and four-level caching.
All contribute to better memory performance.
Interface of a memory module. Common memory modules are as follows:
Single-row in-line Memory modules (SIMM) and dual-row in-line memory modules (DIMMs).
SIMM memory modules are classified into 30 lines and 72 lines.
Compared with SIMM memory modules, DIMM pins increase to 168 lines.
Dimms can be used in a single or mixed manner. Simms must be used in pairs.
According to the way memory works, memory has FPA EDO DRAM and SDRAM (synchronous dynamic RAM) and other forms.
FPA (FAST PAGE MODE) RAM: This is common memory in older computer systems that transmits data every three clock pulse cycles.
EDO (EXTENDED DATA OUT) RAM: EDO memory cancels the time interval between the motherboard and memory cycles. It outputs DATA once every two clock pulse cycles, greatly shortening the access time and increasing the storage speed by 30% EDO memory has been replaced by SDRAMS (SYSNECRONOUS) DRAM Synchronous Dynamic Random access Memory: SDRAM is 168 bits, which is currently used by PENTIUM models and above.
SDRAM locks THE CPU and RAM together through an identical clock so that the CPU and RAM can share a clock cycle and work synchronously at the same speed. The rising edge of each clock pulse starts to transfer data, which is 50% faster than EDO memory.

DDR (DOUBLE DATA RAGE) RAM: memoria ddr4/ hard drives

The next generation of SDRAM, which allows DATA to be transmitted on the rising and falling edges of clock pulses, thus doubling the speed of SDRAM without increasing the clock frequency.
RDRAM (RAMBUS DRAM) memory bus dynamic random access memory;
RDRAM is a new TYPE of DRAM developed by RAMBUS corporation with system bandwidth, chip to chip interface design, which can transfer data over a very high frequency range over a simple bus.
He uses both low-voltage signals to transmit data on both sides of a high-speed synchronized clock pulse.
INTEL will add support for RDRAM to its 820 chipset.
Because the price of such memory is too expensive, it is no longer seen on PCS.
DDR2 (Double Data Rate 2) SDRAM is a new generation of memory technology standard developed by JEDEC (Joint Committee for Electronic Equipment Engineering). The biggest difference between IT and the previous generation OF DDR memory technology standard is that although the basic way of Data transmission is adopted at the same time when the clock rises/falls,
DDR2 memory modules, however, provide four bits of data read prefetch, twice that of the previous generation DDR memory.
In other words, DDR2 memory can read/write data at four times the speed of an external bus per clock, and can run at four times the speed of an internal control bus.
In addition, as the DDR2 standard stipulates that all DDR2 memory is packaged in FBGA format, FBGA provides better electrical performance and heat dissipation, which provides a solid foundation for the stable operation and future frequency development of DDR2 memory.
Recalling the development process of DDR, from the first generation of DDR200 applied to personal computers through DDR266, DDR333 to today's dual channel DDR400 technology, the development of the first generation of DDR has come to the limit of technology, it is difficult to improve the working speed of memory through conventional methods;
With the development of Intel's latest processor technology, the front-end bus has higher requirements on memory bandwidth. DDR2 memory with higher and more stable running frequency will become the trend.

hard drives

1.SDR
2.DDR (generation DDR)
3.DDRII (second generation of DDR)
4.DDRIII
Several kinds of memory gold finger is different, the working voltage is different.
It's not universal. It doesn't slot in.
SDR belongs to the eliminated category, there are no new products, only second-hand.
DDRII is gradually replacing DDR. At present, DDRII with the same capacity has better performance than DDR, but its price is lower than DDR.
DDR faces elimination.
DDRIII has the best performance, is developing and currently costs a lot more than others.
The current mainstream is DDRII, and in a few years it will be DDRIII.