What type of RAM retains information without refreshing, as long as power is on?

Static RAM (SRAM) is known for retaining information without the need for constant refreshing, as long as the power supply is active. This is due to its internal architecture, which uses bistable latching circuitry to store each bit of data. Unlike Dynamic RAM (DRAM), which requires periodic refreshing to maintain data integrity due to its reliance on capacitors that can leak charge, SRAM holds data more persistently within its transistors.

Due to this property, SRAM is typically faster and more reliable than DRAM, making it suitable for cache memory in processors, where quick access to stored data is vital. This characteristic of retaining data without frequent refresh cycles gives SRAM its unique position in computer architecture, especially for high-speed applications. Other types of RAM, like DRAM, RDRAM, and DSRAM, have different mechanisms that necessitate refresh cycles or variations in functionality, which do not provide the same level of data retention as SRAM does while powered.