Kimi K3

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Kimi K3 is Moonshot AI’s 2.8T-parameter, 104B-active Mixture-of-Experts model. NeMo AutoModel provides a native implementation of the text model and loads its public checkpoint without trust_remote_code.

Kimi K3 training in NeMo AutoModel is currently validated only on NVIDIA GB200 systems.

TaskText Generation (MoE, hybrid attention)
ArchitectureKimiK3ForCausalLM
Parameters2.8T total / 104B activated
Layers93 (69 KDA + 24 Gated MLA)
Context Length1,048,576 tokens
HF Orgmoonshotai

Architecture

  • Hybrid attention alternates groups of three Kimi Delta Attention (KDA) layers with a Gated Multi-head Latent Attention (MLA) layer.
  • Attention Residuals operate over 12-layer blocks. Pipeline stages preserve these block boundaries and carry the residual state between stages.
  • Stable LatentMoE routes each token to 16 of 896 routed experts and includes two shared experts. The expert MLPs use SiTU-GLU.
  • The released checkpoint uses MXFP4 weights. The example recipe dequantizes the base checkpoint while loading it for BF16 training.

Parallelism

ParallelismValidated Configuration
FSDP2Full-parameter training
Expert ParallelismEP32
Pipeline ParallelismPP8 with Attention Residual block-aligned stages
Context ParallelismCP2 full-model loss parity at 2K sequence length

The combined EP32 and PP8 configuration is validated on 256 GB200 GPUs.

Example Recipe

RecipeDescription
k3_hellaswag.yaml100-step full-parameter SFT on HellaSwag with FSDP2, EP32, and PP8

Run the Recipe

Allocate 64 GB200 nodes with four GPUs per node through your cluster launcher, then run:

$uv run automodel --nproc-per-node=4 examples/llm_finetune/kimi/k3_hellaswag.yaml

See the Slurm Launcher Guide for multi-node setup and the Large MoE Fine-Tuning Guide for distributed MoE configuration.

References