The recipe follows the expert-only 128x128 block-E4M3 layout used for 0ppxnhximxr/Motif-3-Beta-FP8, while applying it independently to the official Motif-3 weights.
Summary
Architecture: 314B-parameter decoder-only MoE, approximately 13.2B active parameters per token
Quantized weights: gate_up_proj and down_proj in all 51 MoE layers
Quantized tensors: 102
Quantized parameters: 308,029,685,760
Scale format: FP32 inverse scales stored as <weight_name>_scale_inv
Dequantization: W ≈ W_fp8 * scale_inv
Checkpoint tensor size: 629,683,551,500 bytes to 321,729,326,780 bytes, a 48.91% reduction
Embeddings, the language-model head, attention, routers, shared experts, dense layers, MTP layers, normalization layers, and all other non-target tensors remain in their original precision.
Precision compared with the original checkpoint
The following table measures weight-space fidelity, not downstream benchmark accuracy. The FP8 statistics were accumulated over every value in all 102 quantized tensors. “Original” is the exact BF16 checkpoint used as the quantization source.
Metric
Original Motif-3
This FP8 checkpoint
Interpretation
Checkpoint tensor size
629,683,551,500 bytes (586.44 GiB)
321,729,326,780 bytes (299.63 GiB)
48.91% smaller
Routed-expert projection precision
BF16
FP8 E4M3 + FP32 scale per 128x128 block
Expert-only W8A16
Quantized parameters
0
308.03B
102 tensors across 51 MoE layers
Mean cosine similarity
1.000000
0.999650
99.9650% directional similarity
Minimum tensor cosine similarity
1.000000
0.999650
Minimum over the 102 target tensors
Mean relative RMSE
0%
2.6455%
Mean over the 102 target tensors
Maximum relative RMSE
0%
2.6458%
Maximum over the 102 target tensors
Maximum absolute weight error
0
0.06808
Maximum observed element error
NaN or Inf after dequantization
0
0
No non-finite values observed
Non-target tensor equality
Reference
Bit-exact to reference
Verified for non-quantized tensors
Cosine similarity is not “model accuracy.” A paired BF16-versus-FP8 benchmark suite has not yet been completed, so no task-accuracy retention percentage is claimed here.
Validation
The checkpoint was validated in four ways:
The source repository was downloaded at the pinned revision and all 167 source files passed local checksum/presence verification.
The output index contains 2,338 tensors: the original 2,236 tensors plus exactly 102 FP32 inverse-scale tensors.
Three representative 128x128 blocks from each quantized tensor were recomputed from the official BF16 source. All 306 sampled blocks matched the converter's FP8 values and scales exactly.
The quantizer output was cross-checked against vLLM's block-FP8 cast with use_ue8m0=False; sampled values and scales matched exactly.
The local FP8 tensors were also compared with the Beta-FP8 checkpoint and were different, confirming that these are quantized official Motif-3 weights rather than copied Beta weights.
This checkpoint stores arbitrary FP32 inverse scales. The pinned Motif vLLM image supports online block-FP8 conversion from BF16 but does not directly load this serialized layout without a small runtime patch. The reproducible patch and Dockerfile used for the smoke tests are included in serving/.
The following conservative command matches the tested 4x H100 80GB topology. It uses CPU/UVA offload because the model and usable KV cache do not comfortably fit in 4x 80GB without it.
The 512-token context limit above was used only for the constrained H100 smoke test. It is not the model's architectural limit. Larger context lengths need substantially more KV-cache memory and were not validated on this topology. The upstream Motif-3 card recommends H200 or B200-class deployments for the full model.
Each [expert, output, input] tensor is divided into 128x128 blocks. For each block, it stores E4M3 values and an FP32 inverse scale computed from amax / 448.
Limitations
No full downstream benchmark parity run against the original BF16 model has been completed.
The reported fidelity values measure weights, not task accuracy or perplexity.
Long-context behavior was not evaluated.
Direct loading currently requires the included patch against the exact pinned Motif vLLM image.
Generic Transformers loading is not a supported inference path for this serialized FP8 layout.
CPU/UVA offload makes 4x H100 80GB serving possible but can reduce throughput.
For architecture details, intended use, training data, safety considerations, and the original benchmark results, see the official Motif-3 model card.
License and attribution
The upstream Motif-3 checkpoint is published under the MIT license. This repository contains a quantized transformation of those weights. Motif-3 was created by Motif Technologies; this community repository is not an official Motif Technologies release.
