Model record

Flint 40B

Recursive · Apache 2.0 · released · verified

Architecture Mixture of experts
Parameters 39.8B total / ~2.5B active
Context 262,144 tokens
Deployment tier Workstation
Starting memory 13 GB
Recommended 16 GB

What this model is

Recursive reports 39.8B total parameters and approximately 2.5B active parameters per token, including the output head. The active body alone is about 2.2B parameters.

The architecture is mixture of experts. Memory must hold the full weight set, while active parameters affect the speed heuristic. Experts can be offloaded to system memory, but that trades speed for capacity.

Memory and quantization

Decimal GB from published GGUF file sizes. NVFP4 is Recursive's official file; the UD entries and Q8_0 are Unsloth dynamic GGUFs. These are text-only model files, not the 80 GB BF16 checkpoint.

Quantization Published files 8K estimate Smallest comfortable GPU Smallest comfortable Mac Context at smallest GPU / Mac Speed estimate Run commands
UD-IQ1_M 11.35 GB 13.09 GB NVIDIA GeForce RTX 5060 Ti · 16 GB · 16 GB VRAM Mac mini M6 · 24 GB · 24 GB unified memory 109,776 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-iq1_m
UD-IQ2_XXS 11.86 GB 13.59 GB NVIDIA RTX PRO 4000 Blackwell · 24 GB · 24 GB VRAM Mac mini M6 · 24 GB · 24 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-iq2_xxs
UD-Q2_K_XL 13.56 GB 15.30 GB NVIDIA RTX PRO 4000 Blackwell · 24 GB · 24 GB VRAM Mac mini M6 · 24 GB · 24 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-q2_k_xl
UD-IQ3_XXS 14.54 GB 16.27 GB NVIDIA RTX PRO 4000 Blackwell · 24 GB · 24 GB VRAM Mac mini M6 · 24 GB · 24 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-iq3_xxs
UD-Q3_K_XL 18.49 GB 20.23 GB NVIDIA GeForce RTX 5090 · 32 GB · 32 GB VRAM Mac mini M6 · 32 GB · 32 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-q3_k_xl
NVFP4 22.86 GB 24.60 GB NVIDIA GeForce RTX 5090 · 32 GB · 32 GB VRAM Mac mini M6 · 32 GB · 32 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class ollama run flint:40b lms get "Flint 40B"@nvfp4
UD-Q4_K_XL 25.05 GB 26.79 GB NVIDIA RTX PRO 5000 Blackwell · 48 GB (72GB variant) · 48 GB VRAM Mac mini M5 Pro · 48 GB · 48 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-q4_k_xl
UD-Q5_K_XL 29.92 GB 31.65 GB NVIDIA RTX PRO 5000 Blackwell · 48 GB (72GB variant) · 48 GB VRAM Mac mini M5 Pro · 48 GB · 48 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-q5_k_xl
UD-Q6_K_XL 36.32 GB 38.05 GB NVIDIA RTX PRO 5000 Blackwell · 48 GB (72GB variant) · 48 GB VRAM Mac mini M5 Pro · 48 GB · 48 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@ud-q6_k_xl
Q8_0 42.30 GB 44.04 GB NVIDIA RTX PRO 6000 Blackwell · 96 GB · 96 GB VRAM Mac Studio M5 Max · 128 GB · 128 GB unified memory 262,144 / 262,144 tokens Estimate · Fast relative class lms get "Flint 40B"@q8_0

Estimate formula: published weight files + 0.2349 GB per 8K tokens × context / 8K + 1.5 GB runtime overhead. Sizes are decimal GB, not GiB. At 8K context, the smallest listed build is about 13.1 GB before OS and application reserve.

Conservative FP16 estimate from the 14 full-attention layers. The other 35 layers use a 513-token sliding window and are excluded from the per-token linear estimate.

Ollama tags were checked against the linked Ollama library pages on 2026-11-02. LM Studio's lms get suffix selects a file when the search results expose that exact quantization; confirm the local key with lms ls.

KV method source: https://huggingface.co/RecursiveSI/flint/raw/main/config.json

Speed heuristic

Not benchmarked here. The 2.5B active path suggests a faster relative class than a dense 40B model, but expert routing and offload can dominate real throughput.

Active path: 2.5B parameters. This is a relative speed signal only; it is not a tokens/sec benchmark.

If the full weights do not fit in accelerator memory but do fit in system memory, the calculator marks the result as a tight CPU-offload fit. Expect substantially slower generation and verify the runtime's MoE offload support.

Runtimes

  • Ollama
  • llama.cpp
  • SGLang
ollama run flint:40b
lms get "Flint 40B"@ud-iq1_m
lms load <model-key-from-lms-ls> --gpu max --context-length 8192

License restrictions

Apache 2.0 permits commercial use and modification; retain notices and comply with the patent and termination terms.

This is a plain-language summary, not legal advice. Read the linked license before commercial deployment or redistribution.

Known issues

  • Recursive's BF16 serving kit targets one B300 or H200 per replica. The lower-bit GGUF and Ollama builds trade quality and support for consumer hardware.
  • The native context is 262K tokens; a long prompt can exhaust memory even after the weight file fits.
  • Some community conversions and runtimes may lag the custom attention configuration. Verify the chosen runtime against the linked GGUF card.

If it does not fit, try these smaller records

These alternatives have a lower recommended memory target in the current catalog. Open each page to compare the quantization-specific fit before downloading.

27.36B dense / ternary

Bonsai 2

Dense · starting at 8 GB

4.5B effective / 8B stored

Gemma 4 E4B

Dense · starting at 8 GB

FAQ

Model-specific questions

What is the smallest local file for Flint 40B?

The smallest published weight package in this record is UD-IQ1_M at 11.35 GB. The 8K runtime estimate adds 0.23 GB of KV cache and 1.5 GB overhead, for about 13.1 GB before operating-system reserve.

How much memory do the published quantizations need at 8K?

UD-IQ1_M about 13.1 GB at 8K; UD-IQ2_XXS about 13.6 GB at 8K; UD-Q2_K_XL about 15.3 GB at 8K; UD-IQ3_XXS about 16.3 GB at 8K; UD-Q3_K_XL about 20.2 GB at 8K; NVFP4 about 24.6 GB at 8K; UD-Q4_K_XL about 26.8 GB at 8K; UD-Q5_K_XL about 31.7 GB at 8K; UD-Q6_K_XL about 38.1 GB at 8K; Q8_0 about 44.0 GB at 8K. These are calculated estimates using the published weight sizes and the model's KV-cache assumption, not live memory measurements.

Which GPU and Mac configurations are comfortable for Flint 40B?

Against the current catalog, the smallest configurations that clear the 20% headroom target are: UD-IQ1_M: NVIDIA GeForce RTX 5060 Ti · 16 GB; UD-IQ2_XXS: NVIDIA RTX PRO 4000 Blackwell · 24 GB; UD-Q2_K_XL: NVIDIA RTX PRO 4000 Blackwell · 24 GB; UD-IQ3_XXS: NVIDIA RTX PRO 4000 Blackwell · 24 GB; UD-Q3_K_XL: NVIDIA GeForce RTX 5090 · 32 GB; NVFP4: NVIDIA GeForce RTX 5090 · 32 GB; UD-Q4_K_XL: NVIDIA RTX PRO 5000 Blackwell · 48 GB (72GB variant); UD-Q5_K_XL: NVIDIA RTX PRO 5000 Blackwell · 48 GB (72GB variant); UD-Q6_K_XL: NVIDIA RTX PRO 5000 Blackwell · 48 GB (72GB variant); Q8_0: NVIDIA RTX PRO 6000 Blackwell · 96 GB. A larger configuration may still be preferable for longer context or faster memory bandwidth.

What is the right Ollama or LM Studio command for Flint 40B?

Use the command attached to the specific quantization in the table. Ollama tags are taken from the checked Ollama library pages. For LM Studio, use lms get with the displayed quantization suffix, then load the resulting local key from lms ls with --gpu max and the desired context length.

What should I run instead if Flint 40B does not fit?

Smaller catalog alternatives include Bonsai 2, Gemma 4 12B Unified, NVIDIA Nemotron 3.5 Bolt E4B, Gemma 4 E4B. Compare their quantization tables and minimum memory before choosing; a smaller parameter count does not always mean a proportionally smaller download.

Sources

This page is an independent compatibility guide, not official documentation. Verify the primary source before downloading or deploying a model.

Check a specific machine