Summary
Highlights
RAM, or Random Access Memory, is the most common type of memory in computers, but it's not long-term storage like a hard drive or SSD. RAM acts as temporary, high-speed storage for applications and data currently in use, enabling the CPU to process information quickly. Data must be loaded into RAM to be worked with, and results are often saved back to the storage drive.
Instead of individual chips, memory is installed as modules called DIMMs (Dual Inline Memory Module). These have electrical contacts on both sides, making installation and removal simple. For laptops and mobile devices, smaller SO-DIMMs (Small Outline Dual Inline Memory Module) are used, which are about half the size of standard DIMMs.
Modern RAM chips are Dynamic Random Access Memory (DRAM), and most are Synchronous DRAM (SDRAM), meaning they are synchronized with the computer's clock for efficient data transfer. To further increase data transfer speeds, Double Data Rate (DDR) technology was introduced. DDR transfers data on both the rising and falling edges of the clock cycle, effectively doubling the data rate compared to older single data rate memory.
DDR memory comes in different versions, such as DDR3, DDR4, and DDR5, with each new version offering increased speeds and capacity. However, these versions are generally not backwards-compatible due to physical keying on the memory modules preventing incorrect installation. This means a DDR4 module cannot be installed in a motherboard designed for DDR3.