How Flash Attention Conquers the GPU Memory Bottleneck

Flash Attention reveals a counterintuitive truth about transformer performance: memory bandwidth, not computational throughput, is the true limiting factor. By restructuring attention computation to operate within fast on-chip SRAM rather than slower main memory, it achieves 2-4x end-to-end speedup with zero precision loss and no model changes—fundamentally reshaping how we think about GPU efficiency.