Qwen 3.5 397B-A17B · MI325X · Precision Comparison

MI325X: FP8 vs BF16 Precision Comparison

How FP8 and BF16 precision affect Qwen 3.5 397B-A17B inference on MI325X (AMD CDNA 3). Throughput, latency, and cost across LLM workloads. Use the chart controls below to switch sequences and metrics — same interactions as the main inference chart.

Near the low end of the 41–72 tok/s/user interactivity band, at 49 tok/s/user on Qwen 3.5 397B-A17B (MI325X): FP8 runs 347 tok/s/GPU at $1.04/M tokens, BF16 runs 462 at $0.77/M. BF16 is 34% cheaper per token; BF16 delivers 33% more tok/s/GPU. Precision changes affect both inference speed and model quality — consult the evaluation tab for accuracy benchmarks.

At 57 tok/s/user on Qwen 3.5 397B-A17B (MI325X), FP8 delivers 211 tok/s/GPU at $1.69 per million tokens; BF16 delivers 382 tok/s/GPU at $0.94. BF16 is 80% cheaper per token; BF16 delivers 81% more tok/s/GPU. Lower-precision quantization trades model accuracy for throughput — check the evaluation page for quality impact.

FP8 posts 124 tok/s/GPU for $2.86 per million tokens at 65 tok/s/user on Qwen 3.5 397B-A17B (MI325X); BF16 posts 307 tok/s/GPU for $1.17. BF16 is 144% cheaper per token; BF16 delivers 147% more tok/s/GPU. Quantization-level accuracy differences are tracked on the evaluation tab. (Numbers reflect the default 1k/1k selection for this URL — table and chart below update if you change sequence or model in the controls. Each side uses the best available serving configuration for that precision, which may include speculative decoding such as MTP where recipes exist — the same convention as the other comparison pages.)

Qwen 3.5 397B-A17B: FP8 versus BF16 throughput and cost at matched interactivity levels on MI325X
FP8 versus BF16 throughput and cost per million tokens on MI325X for this comparison's canonical default workload.
Interpolated from real benchmark data. Edit target interactivity values below to compare at different operating points.
Metric
Interactivity (tok/s/user)
Interactivity (tok/s/user)
Interactivity (tok/s/user)
Throughput (tok/s/gpu)
FP8:346.6BF16:461.5
FP8:211.0BF16:382.0
FP8:124.3BF16:306.9
Cost ($/M tok)
FP8:$1.040BF16:$0.774
FP8:$1.687BF16:$0.937
FP8:$2.856BF16:$1.170
tok/s/MW
FP8:158969BF16:211704
FP8:96777BF16:175221
FP8:57015BF16:140777
Concurrency
FP8:~30BF16:~41
FP8:~16BF16:~30
FP8:~8BF16:~20

Inference Performance

Inference performance metrics across different models, hardware configurations, and serving parameters.

Vendor:
Aggregation:
Spec Decoding: