GoKawiilWhen a laptop or desktop spec lists 16GB or 32GB of RAM, it's referring to dynamic random-access memory, or DRAM. This is the computer's main working memory, which holds data while programs are running. DDR5 is one current form of DRAM in computers, while phones and other mobile devices commonly use low-power DRAM such as LPDDR5X.
Each DRAM cell stores a bit using a capacitor and a transistor. The electrical charge in the capacitor leaks over time, so DRAM has to refresh its contents repeatedly while the system is running. Once power is removed and those refreshes stop, the stored data disappears.
DRAM can come in forms other than the removable sticks commonly found in desktop PCs. AMD's Ryzen AI Max chips, for example, can work with as much as 128GB of unified memory. The underlying job is still temporary working memory, even when the physical layout looks different from a traditional DIMM (the removable stick-shaped circuit board lined with memory chips that plugs into a motherboard slot).
Static random-access memory, or SRAM, is volatile too. "Static" refers to the fact that SRAM can retain its state without the periodic refresh cycles DRAM needs, provided power is still available. SRAM uses latching circuitry with several transistors per bit, which can provide faster access than DRAM's capacitor-and-transistor cell.
That makes SRAM well-suited to processor caches, where relatively small amounts of frequently needed data can sit close to the CPU. The Ryzen 9 9950X3D (our review) is an unusually cache-heavy example, with 144MB of combined L2 and L3 cache. That's still tiny compared with the gigabytes of DRAM used as main memory, which shows how differently the two volatile technologies are used.