RDRAM is used mainly for video accelerators, and also in the

Ultra 64 from Nintendo. It offers sustained transferrates of around 1000 Mbps, compared to 200 Mbps for ordinary

DRAM. Although it cannot be used as a direct replacement for

existing memory, it is likely that it will replace DRAM and

SDRAM as the main memory system in personal computers as

the bus speeds required by these machines increase. SDRAM

can operate up to around 100MHz, but RDRAM has been

demonstrated by the manufacturers running at 600MHz.