AMD's Matrix Cores Break IEEE 754, So Researchers Built Bit-Exact Models

Accurate Models of AMD Matrix Cores

Matrix multipliers on recent GPUs don't follow IEEE 754, and their undocumented quirks—accumulator width, rounding, subnormal handling—make results irreproducible across devices. Researchers characterize AMD's CDNA 1, CDNA 2, and CDNA 3 matrix cores using targeted test vectors, then build MATLAB models that match hardware bit-for-bit across 10 million random inputs. They also quantify application-level accuracy differences between AMD matrix cores and NVIDIA tensor cores.