diff between SDRAM and DDRAM
yes I know that this is repeat question. I have search EE but I am not satisfied with other answers. I know so much so far
DDR = Dual/Double Data Rate
SDRAM = Synchronous Dynamic RAM (in sync with CPU clock)
I know DDR SDRAM exists because it is in my machine right now. is there a "DDR DDRAM"? I believe there should exist one. what does the first 'D' stand for in DDRAM? I know it is not Dual Data Rate again because last four letters are for Dynamic Random Access Memory.
how do you calculate throughput by looking at the chip's number (PC100, PC133, PC3200, etc.)?
thank you
jaydutt
DDR = Dual/Double Data Rate
SDRAM = Synchronous Dynamic RAM (in sync with CPU clock)
I know DDR SDRAM exists because it is in my machine right now. is there a "DDR DDRAM"? I believe there should exist one. what does the first 'D' stand for in DDRAM? I know it is not Dual Data Rate again because last four letters are for Dynamic Random Access Memory.
how do you calculate throughput by looking at the chip's number (PC100, PC133, PC3200, etc.)?
thank you
jaydutt
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30 points : Hi,actually DDR SDRAM is also called DDRAM.
well, all three of you said the same thing but he got there first.
30 points : 184 pin DDR-SDRAM is available in different configurations: PC1600 (200MHz), PC2100 (266MHz), PC2700 (333MHz), PC3200 (400MHz), PC3500 (433MHz), PC3700 (466MHz) , PC4000 (500MHz) etc.... and more
final quick question: Alhtough memories are rated for particular bus rates, can they operate at slower bus rates?
thank you all.
well, all three of you said the same thing but he got there first.
30 points : 184 pin DDR-SDRAM is available in different configurations: PC1600 (200MHz), PC2100 (266MHz), PC2700 (333MHz), PC3200 (400MHz), PC3500 (433MHz), PC3700 (466MHz) , PC4000 (500MHz) etc.... and more
final quick question: Alhtough memories are rated for particular bus rates, can they operate at slower bus rates?
thank you all.
Yes, they can operate slower without problems. They can operate faster also, but faster operation (overclocking) is not guaranteed and may fail to work proerly, it may also result in overheating (possibly to the point of physical damage).
Just to add to what Watzman said - I concur that USUALLY you can operate memory spec'd for one frequency at another, but it depends on the system. In some older systems spec'd for 168pin SDRAM of PC66 or PC100 configuration, I do find that some of the newer PC133 doesn't operate in the system properly. This is due to several differing factors which I can go into further if you'd like, but suffice it to say that some of the newer higher density modules aren't compatible with some older systems.
Regarding running faster - overclocking the memory - RAM doesn't generally overheat, (unless you've increased the voltage to the memory itself, in which case heat spreaders may be necessary) but it does tend to cause system instabilities when overclocked.
And glad we could help you,
AlbertaBeef
Regarding running faster - overclocking the memory - RAM doesn't generally overheat, (unless you've increased the voltage to the memory itself, in which case heat spreaders may be necessary) but it does tend to cause system instabilities when overclocked.
And glad we could help you,
AlbertaBeef
DRAM = Dynamic Random Access Memory
SDRAM = Synchronous Dynamic Random Access Memory
DDR = Double Data Rate
Double data rate means that the data is transferred between the memory and the memory controller on both edges of the clock pulse. Standard SDRAM (single data rate) transferrs data on only one edge of the clock pulse. Thus, at the same clock speed, DDR SDRAM is twice as fast as SDRAM [SDRAM without the DDR prefix implies single data rate]
All DDR memory is also still SDRAM, even if, for brevity, it's not described as DDR SDRAM. I've never seen DDRAM used before your post.
The bandwidth number (such as PC3200) is calculated by multiplying the number of transfers per second by the memory bus width (e.g. memory that is 32 bits wide is transferring 4 (8-bit) bytes per transfer).