Which RAM technology fetches 4 bits per clock cycle and uses 1.8 volts?

The correct answer pertains to DDR2 SDRAM, which is specifically designed to operate with a voltage of 1.8 volts and fetches 4 bits of data per clock cycle. This technology builds on the original DDR SDRAM by enabling higher data transfer rates while maintaining efficiency through reduced power consumption.

DDR2 enhances performance with a doubling of the bus width compared to traditional SDRAM, allowing for greater amounts of data to be processed at once. This means that for every clock cycle, it can transfer more data, leading to improved overall system performance in scenarios demanding high bandwidth.

In contrast, other options like DDR SDRAM and DDR3 SDRAM operate at different voltage levels or provide different data rates. DDR SDRAM typically uses 2.5 volts but fetches data at a rate lower than DDR2, while DDR3 increases the voltage efficiency further to 1.5 volts but may not match the specific data fetch rate of 4 bits per clock cycle associated with DDR2. This differentiation in technology and specifications is critical in determining the optimal RAM type for various computing needs.