RAM (Random Access Memory) is fast, volatile memory used for active apps. Storage (SSD/UFS/eMMC) is slower, persistent memory for files. More RAM = more apps in memory; more storage = more files saved.
RAM (LPDDR5/5X in phones, DDR5 in laptops) is wiped when the device powers off. It holds the OS, currently-running apps, and active browser tabs. Mainstream phones use 8–12 GB RAM; flagships use 12–16 GB; laptops typically 16–32 GB.
Storage retains data across power cycles. Common types: UFS 3.1/4.0 (mobile), NVMe PCIe Gen 4/5 SSD (laptops, fastest), eMMC (slow, budget devices).
Running low on RAM forces the OS to kill background apps (slower app reopens). Running low on storage hurts everything — the OS uses storage as overflow virtual memory.