Quote:
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Originally Posted by drgrudge
it is cheaper than sdram and besides sdram is static memory and ddram is dynamic memory...
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Dude U need to check ur facts before u post anything....
SDRAM = Synchronous Dynamic Random Acess Memory
DDR-SDRAM (Yes DDR is a Special type of SD) - Double Data Rate SDRAM
Whats the diff.?
Well SDRAM pumpsout data Once very clock cycle
So if u have a RAM that can pump out say 1MB per Clock cycle , then when Ram is running @ a speed of 100Mhz (100x1000 hz) we get 100x1000 MB per second...
Incase of DDRRAM ,Data is pumped out TWICE a clock cycle
So if u a Module that can pump out 1MB , Then since it can pump out twice every clock cycle (Raising and Trailing edge of a Clock Cycle) it can pump out 2MB per clock cycle...
hence @100Mhz we have 100x1000x
2 MB ... (We now have double!! )
In order to make this all simple a DDR400 runs at an Hypothetical 400 Mhz (but Actually its running @ 200Mhz, But it pumps out data twice as much as conventional RAM hence they say its 400MHZ)
Code:
SD RAM
Clock Pulse _|-|_|-|_
^ ^ -- Data
DDR RAM
Clock Pulse _|-|_|-|_
^ ^ ^ ^ -- Data
and BTW SDRAM and DDR are both Dynamic... there is nothing 'Static ' about it.... :roll:
difference between ddr and sd ram
Linear Mode
