SpinQuant W4A4KV4 8-task zero-shot accuracy delta vs fp16, LLaMA-2 7B
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benchmarks/spinquant-w4a4kv4-zeroshot-accuracy-delta-llama2-7bNotes
DELTA = -2.9 pp (64.0 vs 66.9); value holds the magnitude, direction is in the unit and notes. Three ways this number gets misread. (1) It is the BEST published 4-bit result, not a typical one: at identical precision the same table gives LLM-QAT a 22.0-point gap and SmoothQuant a 25.0-point gap. Quoting 2.9 as 'what 4-bit quantization costs' understates the general case by roughly 7x. (2) It is NOT a hardware result. There is no INT4 tensor-core path anywhere: 4x4 INT GEMM is a research Triton kernel plus fake quantization. The accuracy is real; the throughput claim that would normally follow from it is unavailable. (3) The gap is not stable across scale - the same setting leaves 1.4 points on LLaMA-2 13B and 1.7 on 70B, so 2.9 is specifically the 7B figure. Compare the QuaRot ablation (Table 5): the same W4A4W16 setting on LLaMA-3 8B spans 58.6 (QuaRot+RTN) to 65.8 (SpinQuant_had+GPTQ), a 7-point spread between two legitimate 4-bit methods on one model.