Double Data Rate
- Thread starter Zonaria
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fastdude
Active Member
DDR is Double Data Rate, it basically uses a thing called "double pumping" (transferring data on both the rising and falling edges of the clock signal). It achieves twice the bandwidth of SDRAM ranning at the same frequency, using "double pumping".
http://en.wikipedia.org/wiki/DDR2_SDRAM
DDR2 ^
DDR
http://en.wikipedia.org/wiki/DDR_SDRAM
The new standard for modern CPUs is DDR3
http://en.wikipedia.org/wiki/DDR3_SDRAM
Essentially, DDR3>DDR2>DDR[1]
http://en.wikipedia.org/wiki/DDR2_SDRAM
DDR2 ^
DDR
http://en.wikipedia.org/wiki/DDR_SDRAM
The new standard for modern CPUs is DDR3
http://en.wikipedia.org/wiki/DDR3_SDRAM
Essentially, DDR3>DDR2>DDR[1]
fastdude
Active Member
Yeah I can see how that would be a problem, there being only two "edges" to a clock signal. Still, DDR4 is expected in 2012
ScottALot
Active Member
Link?
2048Megabytes
Active Member
Here is some more information on DDR RAM:
Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM) are an improved version of SDRAM (Synchronous Dynamic Random Access Memory). DDR memory runs twice as fast as SDRAM. Double Data Rate SDRAM processes and transfers data twice per each beat of the system clock (thus the term double data rate). The memory has a 64-bit data path when being used in single channel mode. Desktop memory has one notch and uses 184-pins. SO-DIMMs for laptops had 200-pins. This memory uses about 2.5 volts.
Double Data Rate 2 Synchronous Dynamic Random Access Memory (DDR2 SDRAM) is an improved version of DDR SDRAM. It uses less power than Double Data Rate memory and processes data faster. Memory used in desktops has one notch and uses 240-pins. SO-DIMMs for laptops had 200-pins. This memory uses about 1.8 volts. The internal bus of DDR2 fetches 4 bits of data per each beat of the system clock cycle.
Double Data Rate 3 Synchronous Dynamic Random Access Memory (DDR3 SDRAM) is an improved version of DDR2 SDRAM. The memory used in desktops personal computers has one notch and also uses 240-pins but is keyed so it cannot fit into DDR2 memory slots. SO-DIMMs for laptops had 204-pins. The internal bus of DDR3 also fetches 4 bits of data per each beat of the system clock cycle. It has a higher data transfer rate than Double Data Rate 2 memory. This memory uses about 1.5 volts and presently (in January 2009) runs at speeds of PC 6400 to PC 16000.
Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM) are an improved version of SDRAM (Synchronous Dynamic Random Access Memory). DDR memory runs twice as fast as SDRAM. Double Data Rate SDRAM processes and transfers data twice per each beat of the system clock (thus the term double data rate). The memory has a 64-bit data path when being used in single channel mode. Desktop memory has one notch and uses 184-pins. SO-DIMMs for laptops had 200-pins. This memory uses about 2.5 volts.
Double Data Rate 2 Synchronous Dynamic Random Access Memory (DDR2 SDRAM) is an improved version of DDR SDRAM. It uses less power than Double Data Rate memory and processes data faster. Memory used in desktops has one notch and uses 240-pins. SO-DIMMs for laptops had 200-pins. This memory uses about 1.8 volts. The internal bus of DDR2 fetches 4 bits of data per each beat of the system clock cycle.
Double Data Rate 3 Synchronous Dynamic Random Access Memory (DDR3 SDRAM) is an improved version of DDR2 SDRAM. The memory used in desktops personal computers has one notch and also uses 240-pins but is keyed so it cannot fit into DDR2 memory slots. SO-DIMMs for laptops had 204-pins. The internal bus of DDR3 also fetches 4 bits of data per each beat of the system clock cycle. It has a higher data transfer rate than Double Data Rate 2 memory. This memory uses about 1.5 volts and presently (in January 2009) runs at speeds of PC 6400 to PC 16000.
A clock cycle/clock signal is a oscillating frequency.
Zonaria
New Member
fastdude
Active Member
http://en.wikipedia.org/wiki/DDR4_SDRAM
I know wiki cannot always be trusted, but it seems about right if you consider the years between DDR1, 2 3 etc.