There is no need to discuss SRAM. The cache of the CPU is SRAM. It is extremely fast, but the cost is extremely high, so the capacity is very small. Now it is basically the same speed as the CPU main frequency. The earlier P3 in Slot1/A /K7 is 1/2, 1/3, 2/5 speed
SDRAM is Synchronous Dynamic Random Access Memory, synchronous dynamic random access memory, using 3.3v operating voltage, 64-bit bandwidth, SDRAM connects CPU and RAM Locked together by the same clock, the RAM and CPU can share a clock cycle and work synchronously at the same speed. SDRAM is based on a dual memory bank structure, containing two interleaved memory arrays. When the CPU accesses data from one memory bank or array, the other is ready to read and write data. Through the close switching of these two memory arrays, , the reading efficiency can be improved exponentially.
DRAM includes SDRAM and DDR SDRAM. If you are talking about Rumbus' RDRAM, it is a serial memory with a bit width of only 16/32bit, but the operating frequency is extremely high, reaching 800MHz in 2000. Speed, DDR during the same period was only 266MHz, but this memory belongs to Rumbus patented technology, and the licensing fee is extremely high, so it has now withdrawn from the desktop market, and is still used in some servers. In addition, his biggest customer is SONY PS3 now, but the specifications have been further upgraded, called YellowStone
DDR in front of DDRSDRAM is Dual Data Rate, double rate, 2bit pre-reading, up and down reading and writing at the same time, which is equivalent to the frequency of SDRAM The current DDR2 is 4bit pre-read