This document discusses data-level parallelism in vector, SIMD, and GPU architectures. It covers Flynn's taxonomy of parallel computers, including single instruction stream, single data stream (SISD); single instruction stream, multiple data streams (SIMD); multiple instruction streams, single data stream (MISD); and multiple instruction streams, multiple data streams (MIMD). It also discusses vector architectures, SIMD extensions, and graphics processor units (GPUs) that can exploit data-level parallelism. Key optimizations for vector architectures include multiple lanes, vector length registers, vector mask registers, memory banks, stride, scatter-gather, and programming techniques.