Difference between SD RAM & DDR RAM????

SD RAM stands for Single Data Random Access Memory. It has a different paging system, for those of you who dont know what paging is, it is the swaping of files from your hard drive to your RAM Module. DDR stands for Double Data Rate RAM, its paging system swaps 2 pieces of data at a time

DDR is faster than sd, becaise ddr uses dual channels unlike sd which uses single channel.

here is pretty clear explanation from wiki SDRAM means synchronous dynamic random access memory which is a type of solid state computer memory. Other dynamic random access memories (DRAM) have an asynchronous interface which means that it reacts as quickly as possible to changes in control inputs. SDRAM has a synchronous interface, meaning that it waits for a clock signal before responding to its control inputs. It is synchronized with the computer's system bus, and thus with the processor. The clock is used to drive an internal finite state machine that pipelines incoming instructions. This allows the chip to have a more complex pattern of operation than DRAM which does not have synchronizing control circuits. Pipelining means that the chip can accept a new instruction before it has finished processing the previous one. In a pipelined write, the write command can be immediately followed by another instruction without waiting for the data to be written to the memory array. In a pipelined read, the requested data appears a fixed number of clock pulses after the read instruction. This delay is called the latency and is an important parameter to be considered when purchasing SDRAM for your computer. It is not necessary to wait for the data to appear before sending the next instruction. SDRAM chips are rated according to their maximum clock rate and their read cycle time. Clock rate is directly proportional to maximum bandwidth and is affected primarily by the speed of the internal state machine and interface circuitry. Read cycle time affects the delay between issuing a command and initiating the corresponding operation and is determined primarily by the speed of the memory cells themselves. while ddr is like this DDR SDRAM or double-data-rate synchronous dynamic random access memory is a type of memory integrated circuit used in computers. It achieves greater bandwidth than the preceding single-data-rate SDRAM by transferring data on both the rising and falling edges of the clock signal (double pumped). This effectively nearly doubles the transfer rate without increasing the frequency of the front side bus. Thus a 100 MHz DDR system has an effective clock rate of 200 MHz when compared to equivalent SDR SDRAM, the “SDR” being a retrospective designation. With data being transferred 64 bits at a time DDR RAM gives a transfer rate of (memory bus clock rate) × 2 (for dual rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Thus with a bus frequency of 100 MHz, DDR-SDRAM gives a max transfer rate of 1600 MB/s.

Sdram are for pentium 3 motherboard and ddr are for pentium 4 motherboard. DDR memory are more faster than sdram memory.