DIRECT RAMBUS DRAM - One possible future successor to SDRAM, and competitor to DDR SDRAM. DRDRAM (also now simply called RDRAM) was originally developed by Rambus, Inc. This RAM architecture is capable of speeds starting at 266, 356, and 400MHz, and transfers data on the up and down ticks of a clock cycle, where standard SDRAM tops out at about 200MHz. You may see RDRAM referred to at 532, 712, and 800MHz, but that is actually 266*2, 356*2, and 400MHz*2, where the *2 denotes transfer on the up and down tick of the clock. Intel picked RDRAM to be the future of RAM for PCs, but RDRAM ran into many stumbling blocks due to the complexity of manufacturing it. RDRAM was used in the popular Nintendo 64 game machine for its high-speed capabilities and low pin count, necessary for the intense 3D rendering being done on a low complexity system. RDRAM started out using a 16- bit bus, while SDRAM and DDR have 64-bit buses. Thus, 100MHz SDRAM has half the throughput of RDRAM at 400MHz (100*64 = 6,400Mbits/second; 400*2*16 = 12,800Mbits/second). However, newer RDRAM uses a 32-bit bus and is clocked up to 533MHz*2. Still, it never achieved dominance in the PC market. |
DIRECT RAMBUS DRAM Definition
