1. The birth of the memory stick |bNF
When the CPU in the work, the need to read data from the hard disk and other external memory, but due to the hard disk "warehouse" is too large, and the distance from the CPU is also very large. However, because the hard disk is too large and far away from the CPU, the transportation of "raw" data is slow, resulting in the CPU's productivity being greatly reduced! In order to solve this problem, people in the CPU and external memory, built a "small warehouse" - memory. /
Although the memory capacity is not large, generally only a few dozen MB to a few hundred MB, but the transit speed is very fast, so that when the CPU needs data, some of the data can be stored in the memory beforehand, in order to solve the CPU's urgent needs. Since memory is only a "transit warehouse", it cannot be used to store data for a long time. Memory, also known as randomized memory, loses all data after a power failure. Hard disks do not.
2. Common memory sticks,
Currently, there are three main types of memory used in PCs: SDRAM, DDR SDRAM, and RDRAM. xt
Once upon a time, the mainstream-SDRAMB`<*
SDRAM (Synchronous DRAM), which is the most popular type of memory, has been used to store data for a long time. SDRAM (Synchronous Dynamic Random Access Memory) is a type of memory stick with gold fingers on both sides, which is directly inserted into the memory stick slot, so this structure is also called "Dual Inline Direct Mode", which is called "DIMM" in English. DIMM". The majority of memory sticks currently available are of this "DIMM" type. DDR SDRAM (DDR for short) is an SDRAM that utilizes DDR (Double Data Rate SDRAM) technology. Compared to regular SDRAM, DDR SDRAM can transfer data twice in the same clock cycle, while SDRAM can only transfer data once. :i
In terms of form factor DDR memory sticks are not that different compared to SDRAM, they have the same length and the same pin distance. Except that DDR memory sticks have 184 pins and only one notch in the gold finger, while SDRAM memory sticks are 168 pins and have two notches..." ?H0B
DYU Yueyang County Branch Forum -- Radio and Television University Yueyang County Branch Forum Y^Depending on the operating frequency of a DDR memory stick, it is divided into various types, such as DDR200, DDR266, DDR333, DDR400, and so on: like SDRAM, DDR is synchronized with the system bus frequency, but because of the double data transfer, the DDR operating at 133MHz is equivalent to SDRAM at 266MHz, and is thus referred to as DDR266. cX
Tip: The operating frequency indicates the maximum frequency at which the memory can operate stably, e.g., PC133 standard SDRAM operates at 133MHz, while DDR266 DDR operates at 266MHz. For memory, the higher the frequency, the greater the bandwidth.P|B
In addition to labeling DDR memory sticks with their operating frequency, they are also sometimes labeled with a bandwidth value, for example, DDR 266 has a memory bandwidth of 2100MB/s, so it's labeled again with PC2100, and so DDR333 is PC2700 and DDR400 is PC3200. g99
Tip: Memory bandwidth, also known as the "data transfer rate", is the amount of data passing through memory per unit of time, and is usually expressed in gigabytes per second (GB/s). We use a short formula to illustrate the calculation of memory bandwidth: Memory Bandwidth = Operating Frequency x Bit Width/8 x n (clock pulse up and down edge transfer coefficients, the coefficient for DDR is 2). $%C
DDR memory sticks have become today's mainstream memory products due to their low price and excellent performance. Outdated Aristocrat - RDRAM'8
RDRAM (Memory Bus Dynamic Random Access Memory) is a new type of DRAM developed by Rambus.RDRAM is clocked at a much higher frequency even though its bit-width is narrower than the 64-bit of SDRAM and DDR. Visually, RDRAM memory sticks are somewhat similar to SDRAM and DDR SDRAM memory sticks. Technically, RDRAM is a more advanced memory, but due to its high price, it was not practical to popularize it in the market. Today's RDRAM has been withdrawn from the general desktop market.Jn^Lm
3. Memory Packaging xS{
Currently, there are three main types of memory packages, such as TSOP, BGA, and CSP, and the packaging method also influences the performance strengths and weaknesses of the memory stick.m
TSOP Package: TOSP (Thin Small BGA is called "Ball Grid Array Package", its biggest feature is that the number of pins of the chip increased, the assembly yield increased. The use of BGA packages can make memory capacity increase two to three times in the case of the same volume, compared with TSOP, it has a smaller size, better thermal performance and electrical performance. #bfzvx
DYNAMIC UNIVERSITY OF YUEYANG BANK FORUM -- Radio and Television University of Yueyang County Forum q-~x:CSP package: CSP (Chip Scale Package) as a new generation of packaging, and its performance has been greatly improved. CSP package is not only smaller, but also thinner, and better able to improve the memory chip for a long time, the reliability of the operation, the chip speed is also increased. CSP package is not only smaller in size, but also thinner, which can improve the reliability of long-time operation of memory chips, and the speed of the chip has also been greatly improved. Currently, this package is mainly used for high-frequency DDR memory.'' s}#[_
The forum of Yueyang County Branch of Dalian University -- Yueyang County Branch of Dalian University of Radio and Television 3
1. The clock cycle (TCK) s[{
TCK is the abbreviation of Clock Cycle Time, which is the memory clock cycle. It represents the maximum operating frequency at which the memory can operate, and the smaller the number, the higher the frequency at which the memory can operate. The clock cycle is inversely proportional to the operating frequency of the memory, i.e., TCK = 1/F. For example, a memory chip labeled "-10", "-10" means that it runs at a clock cycle of 10ns, i.e., the clock cycle is 10ns, i.e., the clock cycle is 10ns, i.e., the clock cycle is 10ns. For example, a memory chip labeled "-10", "-10" means that it runs on a clock period of 10ns, which means that it can work normally at a frequency of 100MHz.B}a{?5
2. TAC (Access Time From CLK) /h+L
TAC (Access Time From CLK) means "access time". Unlike clock cycles, TAC simply represents the time it takes to access data. For example, a memory chip labeled "-7J" indicates that the access time of the memory stick is 7ns. the shorter the access time, the better the performance of the memory stick. for example, if two memory sticks are working at 133MHz, one of them has an access time of 6ns, and the other one has 7ns, then the former is better than the latter, and the latter has a higher speed than the latter. The former is better than the latter.8
3. CAS Latency (CL)8
CL (CAS Latency) is an important indicator of memory performance, it is the response time of the memory to longitudinal address pulses. When the computer needs to read data to the memory, before the actual reading there is generally a "buffer period", and the length of the "buffer period" is the length of the CL. The lower the CL value of the memory, the better, therefore, shorten the period of CAS to help speed up the memory of the same frequency under the working speed.F43}e
4. Parity check (ECC) HIIA^
Memory is a kind of data transit "storehouse", and in the process of frequent transit, once the wrong The ECC is a data checking mechanism. ECC is a data checking mechanism, which can not only determine the correctness of the data, but also correct most of the errors. This is not the case for PCs, which are generally used in high-end server computers. oK9pld
Currently, the mainstream memory on the market includes SDRAM and DDR SDRAM, and the memory stick brands are Sentron, Kingston, Samsung, Apacer, Regal, Hyundai, and so on. oK9pld
The main reason for this is that it is not the only way to get the most out of your PCs, but it is the only way for you to get the most out of your PCs.