The Amiga distinguishes two RAM types: Chip RAM (also Chip Memory) is memory accessible by both the CPU and custom chips (Agnus, Denise, Paula). Chip RAM is needed for graphics (bitplanes, sprites), audio samples, and disk I/O. Maximum: 512KB (OCS A500), 1MB (Fat Agnus), 2MB (ECS/AGA). Fast RAM is memory only the CPU can use — without DMA contention, hence 'fast'. CPU code runs significantly faster from Fast RAM. Fast RAM is added via Zorro slots or trapdoor expansions. An Amiga with lots of Fast RAM but little Chip RAM can have issues when programs need Chip RAM for graphics.