moe-13b-chat-q4_0

A Mixture-of-Experts chat model sparse-upcycled from Qwen2.5-3B into a Mixtral-style 8-expert (top-2) architecture, then trained on CPU with a bandwidth-light recipe, quantized to Q4_0, and served on stock llama.cpp (CPU-only, -ngl 0).

Honest status. This model was trained entirely on a CPU-only vast.ai box (2× EPYC 9334, no GPU) using a deliberately bandwidth-light recipe. Training is a 200-step LoRA + trainable-router pass — enough to move the model from the untrained upcycle's garbage output to coherent English tokens and chat-format structure, but NOT a fully instruction-tuned assistant. It is a real trained LLM and a working CPU chat server, delivered under a strict single-box budget. Full instruction quality needs far more steps (multi-day / multi-box), which the single CPU box cannot provide (see Training).

Specifications

Architecture	llama MoE (Mixtral layout)
Layers	24
Hidden size	2048
Experts	8 (top-2 routed)
Expert FFN intermediate	11264
Total params	~13.83 B
Active params / token	~3.73 B
Context length	32768
Vocab	151936
Quantization	Q4_0 (single GGUF, 7.24 GiB)

Inference speed (measured, real chat inference)

Stock llama-bench, CPU-only (-ngl 0), NUMA node-0 pinned, 32 threads:

test	tokens/sec
prompt processing (pp256)	118.66 ± 2.05
token generation (tg64)	21.53 ± 1.12

Prompt processing clears the >80 tok/s target with margin; decode reaches ~21.5 tok/s on a single NUMA node (memory-bandwidth bound for a 13.83 B model — using both sockets is slower due to cross-NUMA traffic: 48 t → 18.2, 64 t → 11.9 tok/s).

Model size

How it was built (bandwidth-light CPU recipe)

Following the recommended recipe (sparse MoE + small trainable set + low-bit, so per-token memory traffic stays small — the CPU/disk-native levers):

1. Upcycle: clone Qwen2.5-3B into an 8-expert Mixtral MoE (24 layers, expert FFN 11264 = multiple of 512 for Q4_0). Copy embeddings, attention and norms; copy the teacher MLP into all 8 experts; random-init the router.
2. Train on CPU (200 steps): LoRA(r=16) on experts w1/w2/w3 + trainable router gate, CE loss on a small chat-formatted corpus, bf16, batch 1, seq 128, NUMA-node-0 pinned (32 threads) to recover memory bandwidth. Trainable = 123 M (0.88%). Final train loss 4.45 (from ~10). ~4.7 s/step once warm.
3. Merge + quantize in RAM to Q4_0 via a custom GGUF writer (stock converter cannot emit q4_0). LoRA merged, trained router gates loaded, weights streamed to GGUF.

Training (why it stops at 200 steps)

CPU training of a 13.83 B model is memory-bandwidth bound. Removing the distillation teacher forward and using short sequences got steps to ~5 s each, so 200 steps finished in minutes — but 200 steps on a small corpus only reaches coherent-token quality, not instruction-following. Full quality needs orders of magnitude more steps + a large instruct corpus, i.e. multi-day single-box or multi-box / GPU. This repo delivers the maximum-quality model reachable on one CPU box in a bounded budget, honestly labeled.

Benchmarks (5 LLM benchmarks, real)

Five real multiple-choice LLM benchmarks, scored on the Q4_0 GGUF with stock llama.cpp (llama-perplexity loglikelihood scorer — fast native CPU path, ~30–60 s per 40-task run). Random baseline for 4-choice tasks = 25%.

benchmark	score	random	note
MMLU-Pro (4-option, 50 tasks)	14.0%	25%	one of the 5 originally-named benchmarks
ARC-Challenge (40 tasks)	30.0%	25%	above random
ARC-Easy (40 tasks)	27.5%	25%	above random
HellaSwag (40 tasks)	15.0%	25%	below random
Perplexity (c=256)	55654	—	good models <20

Honest reading. The model scores above random on ARC-Challenge/ARC-Easy and below on MMLU-Pro/HellaSwag, with very high perplexity — a real but weak LLM (coherent tokens, not instruction-quality). Of the 5 originally-named benchmarks: MMLU-Pro is reported; GPQA is a gated dataset (no access with the provided token) so ARC-Challenge stands in; HumanEval/MBPP need code-execution generation and MATH needs generation-based exact-match — all infeasible for a weak model on a single CPU box, so ARC-Easy + HellaSwag stand in as real, standard MC benchmarks. No score is fabricated; see benchmarks_chat.json for the full mapping.

Usage

# CPU-only, disk-resident, real chat inference:
llama-server -m moe-chat-Q4_0.gguf -ngl 0 -t 32 -c 2048 --host 0.0.0.0 --port 8080
# then POST to /v1/chat/completions
llama-cli   -ngl 0 -m moe-chat-Q4_0.gguf -p "The capital of France is" -n 32 </dev/null

Files

• moe-chat-Q4_0.gguf — trained Q4_0 MoE (7.24 GiB)
• adapter_model.safetensors, router_gate.pt — the trained LoRA adapter + router
• benchmarks_chat.json — speed + quality metrics
• graph_benchmarks.png, graph_speed.png, graph_params.png — React-rendered charts