تفاوت ظاهری بین Ddr ، Ddr2 ، Ddr3

[manouchehr6300]

کسی میدونه Ddr ها از نظر ظاهری چه تفاوتی با هم دارند؟

[mhaf]

از نظر ظاهری هیچ تفاوتی ندارند.
کاملا یک شکل هستند.

[hardware2000]

کسی میدونه Ddr ها از نظر ظاهری چه تفاوتی با هم دارند؟

اون زائده زیرشون با هم فرق داره

[manouchehr6300]

از نظر ظاهری هیچ تفاوتی ندارند.
کاملا یک شکل هستند.

کی گفته از نظر ظاهری فرقی ندارن.من مطمئنم ولی نمیدونم چه فرقی

[آنتی]

به نام خدا
سلام خدمت دوستان
مسلما فرق دارد چون اگر فرقي نداشت كه همه رم ها روي همه مادربورد ها جواب ميداد
وفرق آن هم فاصله گودي رم با طرفين رم است
موفق باشيد

[behnam_tr]

فکر میکنم روی رم های ddr یک زایده و روی رم های ddr2 دو زائده هست....

تنها تفاوت ظاهری رم در این زائده و شکاف هاست.....

[bahman26]

من فکر کنم روی ddrII یک شکاف باشه روی ddrI دو شکاف ddrIII نمیدونم( خودمII دارم)

[taia]

عکس بالایی مربوط به DDR1 و پایینی مربوط به DDR2
غیر از تفاوت ظاهری آشکار، بریدگی وسطی در DDR2 دقیقا در وسط هست ولی در DDR1 کمی نامتقارن هست، این تفاوت خیلی غیر محسوس به نظر می آید ولی به خاطر همین تفاوت نمی تونید از DDR2 جای DDR1 و یا بالعکس استفاده کنید.
البته این تفاوت در رم لپ تاپها بیشتر نمایان هست.
[ برای مشاهده لینک ، لطفا با نام کاربری خود وارد شوید یا ثبت نام کنید ]



من فکر کنم روی ddrII یک شکاف باشه روی ddrI دو شکاف ddrIII نمیدونم

دو شکاف مربوط به SDRAM ها هست


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[H A M E D]

در ضمن تعداد Pin ها يا پايه هاي اين چند نوع رم هم كاملا با هم فرق دارهو چون اندازه و ابعاد اونها با هم يكي هست جهت جلوگيري از اشتباه جازدن و صدمات سخت افزاري ناشي از اين كار شيار روي پايه رم رو هم جابجا كردن كه مثلا رم Ddr2 روي پايه Ddr قابل نصب نباشه و بالعكس.

[mainsoft]

SD, DDR, DDR2 and DDR3 are all different types of RAM (Random Access Memory). RAM is a kind of computer memory that temporarily stores information, improving your systems performance. Or in other words RAM simply holds data for the processor. The processor also has its own memory known as the L2 cache, the cache lies between the processor and the RAM. The processor sends and retrieves data from this cache, when this cache overflows data is sent to the RAM.

There are mainly four types of RAM; SD, DDR, DDR2 and DDR3. They differ in the way they operate and mainly in their operation speeds. All RAM's used in computers today have a synchronous interface meaning they wait for a clock signal before it can respond to clock signals.

SD RAM:

SDRAM stands for synchronous dynamic random access memory. SDRAM is Single Data Rate meaning that SDRAM can accept one command and transfer one word of data per clock cycle. As mentioned above SDRAM's have synchronous interface therefore they depend on the computer clock signals to perform operations. Typical speeds of SDRAM are 100 and 133 MHz.

DDR SDRAM:

DDR SDRAM stands for double data rate synchronous dynamic random access memory. DDR RAM transfers data twice per clock cycle, hence the name double data rate. DDR clock speeds range between 200 MHz (DDR-200) and 400 MHz (DDR-400). DDR-200 transfers 1600 MB/s, while DDR-400 transfers 3200 MB/s.

DDR2 SDRAM:

DDR2 SDRAM stands for double data rate 2 synchronous dynamic random access memory.DDR2 is twice as fast as DDR which means twice as much data is carried to the module for each clock cycle. Also due to the design improvements DDR2 consumes less power as compared to the DDR memory. DDR2 speeds range between 400 MHz (DDR2-400) and 800 MHz (DDR2-800). DDR2-400 transfers 3200 MB/s. DDR2-800 transfers 6400 MB/s.

DDR3 SDRAM:

So by now after reading the above it is quite obvious what DDR3 SDRAM stands for, double data rate 3 synchronous dynamic random access memory. In theory DDR3 is supposed to act twice as fast as DDR2 memories. Thus DDR3 speeds range between 800 MHz (DDR3-800) and 1600 MHz (DDR3-1600). DDR3-800 transfers 6400 MB/s; DDR3-1600 transfers 12800 MB/s.

[ برای مشاهده لینک ، لطفا با نام کاربری خود وارد شوید یا ثبت نام کنید ]

[mainsoft]

The difference between DDR2 and DDR3 On the appearance, both DDR3 and DDR2 use 240 pins and you can hardly see any differences between them. The only difference is the position of the key notch that prevents users from inserting the wrong type of RAM into their motherboards. The shift in the position of the key notch also means that DDR3 is not compatible with DDR2 and a separate DIMM slot has to be used.


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Other than the difference in key notch position, DDR3 RAM is also due to run at a higher frequency than DDR2 RAM. The specification provided by JEDEC ([ برای مشاهده لینک ، لطفا با نام کاربری خود وارد شوید یا ثبت نام کنید ]) provides more insight to its performance.


Official JEDEC Specifications




DDR 2
DDR3


Transfer Speed
400 – 800 Mbps
800 – 1600 Mbps


Voltage
1.8V +/- 0.1V
1.5V +/- 0.075V


Internal Banks
4
8


Prefetch
4bits
8 bits


Termination
Limited
All DQ signals


Topology
Conventional T
Fly-by


CAS Latency
3 – 5
6 – 10


Thermal Sensor
No
Yes (optional)


When JEDEC set the standard for DDR2 RAM, it never intends to make it run beyond 800MHz. The official specification states that DDR speeds ran to DDR-400, DDR2 from 400 to 800, and DDR3 800 to 1600. Due to the fact that DDR2 800 and 1066 (an overclock version of DDR2 800) exist, DDR3 800 and 1066 will become an overlap speed with that of DDR2. As such, it will only be 1333 that is the first DDR3 speed to have better frequency/speed performance over the DDR2 RAM.
While the difference between DDR and DDR2 RAM lies in the doubling of the frequency bus, the DDR3 works by doubling the prefetch data. This is achieved by doubling the internal bank to 8. Each internal bank can process 1 bit of data. DDR2 SDRAM have only 4 internal banks and process 4-bit samples, DDR3 SDRAM uses 8 internal banks to carry out 8-bit prefetch. The impact of the additional internal banks means that the DDR3 SDRAM could double the data transfer rate without having to make modifications to the original design.

Another advantage of DDR3 is the reduced voltage requirement. The required voltage for DDR3 is 1.5V, a 16% reduction of the DDR2 1.8V. This could translate to a 30% reduction in power consumption compared with DDR2 RAM operating at the same speed. Additional built-in power conservation features with DDR3 include partial refresh and thermal sensor that could allow the system to save further power by providing minimum refresh cycles when the system is not in high performance mode.
A point that requires attention and that brings DDR2 RAM back to the game is the price of the DDR3 RAM. A 1GB DDR3 1066MHz RAM is currently selling at over $200, which is double the price of a 1GB DDR2 1066MHz RAM. While there is no significant improvement of the DDR3-1066 RAM over DDR2-1066 RAM, there really isn’t any compelling reason to upgrade your current DDR2 RAM.
Conclusion
In the near future, it is inevitable that DDR3 is going to replace DDR2 as the standard for memory RAM. At this current moment, the hefty price hardly make it a ‘must-upgrade’ component, considering that you can get a DDR2 RAM operating at the same speed for under $150. Until the time when higher speed DDR3 RAM are more readily available and the price fall to a reasonable range that is comparable to DDR2, it is better to remain with your DDR2 RAM.:n28: