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Open-weight model · Image and text to text

Step-5-Preview-NVFP4-Local

by Brandon Music brandonmusic/Step-5-Preview-NVFP4-Local

Step-5-Preview-NVFP4-Local is an open-weight model for image and text to text from Brandon Music, released under other. It has 338.5B parameters and a 1,048,576-token context. At 16-bit it needs about 812.5 GB of GPU memory, which fits on 3x MI355X from $7.77 an hour; at 4-bit, 203.1 GB on 1x MI325X from $2.00, at the lowest prices in the SAVRN Index.

A lossless repack of stepfun-ai/Step-5-Preview-NVFP4 (revision bc246cc2848e17b37f377eda8fd825c5b3018d1f), 17.1 GB smaller.

Parameters338.5B
Context1,048,576
Weights377.0 GB
Licenseother
AccessOpen weights
Monthly Downloads—

Runs On

What it takes to serve Step-5-Preview-NVFP4-Local (338.5B parameters): the memory its weights need at each precision, and the cheapest way to rent enough data-center GPUs to hold them.

PrecisionWeightsMemory neededCheapest setupPer hourAlso fits
16-bit 677.1 GB 812.5 GB 3x MI355X (288 GB)
Vultr
$7.77 4x MI325X $8.00 · 5x MI300X $9.25
8-bit 338.5 GB 406.3 GB 2x MI325X (256 GB)
Vultr
$4.00 2x MI355X $5.18 · 3x MI300X $5.55
4-bit 169.3 GB 203.1 GB 1x MI325X (256 GB)
Vultr
$2.00 1x MI355X $2.59 · 2x MI300X $3.70

Memory is the weights at that precision plus 20% for the runtime and a short context; a long context needs more. Prices are the lowest on-demand hourly rates in the SAVRN Index, read Oct 20, 2026.

Step-5-Preview-NVFP4-Local on every accelerator the SAVRN Index prices, at every precision

Model Card

A lossless repack of stepfun-ai/Step-5-Preview-NVFP4 (revision bc246cc2848e17b37f377eda8fd825c5b3018d1f), 17.1 GB smaller. The NVFP4 block scales of the routed experts are stored in b12x's compressed scale format (CSF), the lossless format introduced with nvidia/Qwen3.8-Flash-Next-FP4-Local. Every FP4 weight byte and every other tensor is identical to StepFun's checkpoint, and every scale decodes to StepFun's exact bytes, so this checkpoint computes exactly what Step-5-Preview-NVFP4 computes. Step 5 Preview is StepFun AI's model: a sparse mixture of experts with 600B total and 27B active parameters, text and image input, up to 1M tokens of context. Model card: stepfun-ai/Step-5-Preview.…

Excerpt from the card by Brandon Music, licensed other.

Configuration

Architecture
Step5ForConditionalGeneration
Context length (tokens)
1,048,576
Layers
92
Hidden size
4,096
Feed-forward size
13,824
Attention heads
64
Head dimension
192
Vocabulary size
128,896
Experts active per token
8
Sliding window (tokens)
512
Stored precision
bfloat16
Model type
step5_vl
Quantization
modelopt

Identity and Version

Repository
brandonmusic/Step-5-Preview-NVFP4-Local
Publisher
Brandon Music
Task
Image and text to text
Modality
Image and text
Library
Not stated by the source
Parameters
338.5B parameters
Languages
csf, moe
Revision
fb91fb27f3b36f3e056aedb7ed1c5eb51f51f861
First published
2026-10-16
Last updated
2026-10-16

Files and Weights

109 files, 377.0 GB in total. The weights are 95 files totalling 377.0 GB in safetensors.

Weights95 files · 377.0 GB
Configuration6 files · 448.4 KB
Tokenizer2 files · 10.1 MB
Documentation3 files · 23.6 KB
Other2 files · 15.9 KB
Repository1 file · 1.5 KB
Every file
FileTypeSizeSHA-256
model-extra-000.safetensorsWeights5.5 GB 5798d715bcae
model-extra-001.safetensorsWeights1.7 GB 3d8965d16468
model-layer-000.safetensorsWeights554.2 MB dce1dfebe142
model-layer-001.safetensorsWeights554.2 MB 1e640e5a6d78
model-layer-002.safetensorsWeights554.2 MB e0d41a65430b
model-layer-003.safetensorsWeights3.8 GB f22adafe7d25
model-layer-004.safetensorsWeights3.8 GB 54139da206aa
model-layer-005.safetensorsWeights3.8 GB 693237f7b235
model-layer-006.safetensorsWeights3.8 GB 177f06f544b2
model-layer-007.safetensorsWeights3.8 GB fd10603b632b
model-layer-008.safetensorsWeights3.8 GB fa9b9a914e97
model-layer-009.safetensorsWeights3.8 GB cf68a81883b6
model-layer-010.safetensorsWeights3.8 GB 9379f99ca009
model-layer-011.safetensorsWeights3.8 GB 9335e4e83441
model-layer-012.safetensorsWeights3.8 GB 2d92cce47dc7
model-layer-013.safetensorsWeights3.8 GB 74a31d285941
model-layer-014.safetensorsWeights3.8 GB 127f13357bc5
model-layer-015.safetensorsWeights3.8 GB 43b0f0a7ef29
model-layer-016.safetensorsWeights3.8 GB 7700a904da28
model-layer-017.safetensorsWeights3.8 GB 34ad4068bf6a
model-layer-018.safetensorsWeights3.8 GB de6e7999b4c0
model-layer-019.safetensorsWeights3.8 GB c91132a96322
model-layer-020.safetensorsWeights3.8 GB 959641cd510f
model-layer-021.safetensorsWeights3.8 GB cc60dd73fb76
model-layer-022.safetensorsWeights3.8 GB 1345de40319f
model-layer-023.safetensorsWeights3.8 GB c1cc3cc4bf88
model-layer-024.safetensorsWeights3.8 GB 47c97cf51288
model-layer-025.safetensorsWeights3.8 GB 200f666c8049
model-layer-026.safetensorsWeights3.8 GB c61813fcaf7e
model-layer-027.safetensorsWeights3.8 GB 39b23ac49206
model-layer-028.safetensorsWeights3.8 GB e0318a186d7b
model-layer-029.safetensorsWeights3.8 GB 93a0edad8e15
model-layer-030.safetensorsWeights3.8 GB d91cdc38a42c
model-layer-031.safetensorsWeights3.8 GB b3bdd8835fe4
model-layer-032.safetensorsWeights3.8 GB de97705eb8ef
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model-layer-036.safetensorsWeights3.8 GB 9930d871ee46
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model-layer-041.safetensorsWeights3.8 GB 917997e42a5f
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model-layer-043.safetensorsWeights3.8 GB 585bc7be46e3
model-layer-044.safetensorsWeights3.8 GB 765081e215bc
model-layer-045.safetensorsWeights3.8 GB c19ebb48cabd
model-layer-046.safetensorsWeights3.8 GB 7addbcabce24
model-layer-047.safetensorsWeights3.8 GB 1eaf341f3ffe
model-layer-048.safetensorsWeights3.8 GB 71cb6b3f1d0c
model-layer-049.safetensorsWeights3.8 GB e2ecc66a0472
model-layer-050.safetensorsWeights3.8 GB 4f99b20ff508
model-layer-051.safetensorsWeights3.8 GB 23de2547df63
model-layer-052.safetensorsWeights3.8 GB 30e9750f46bb
model-layer-053.safetensorsWeights3.8 GB d57232a0924f
model-layer-054.safetensorsWeights3.8 GB 29a3bb0aef78
model-layer-055.safetensorsWeights3.8 GB 72921a53c029
model-layer-056.safetensorsWeights3.8 GB 69302ad1eb10
model-layer-057.safetensorsWeights3.8 GB 7e0677ba718c
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model-layer-059.safetensorsWeights3.8 GB 575cb3e70fc6
model-layer-060.safetensorsWeights3.8 GB 437044496f64
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model-layer-062.safetensorsWeights3.8 GB f2bb04c80a14
model-layer-063.safetensorsWeights3.8 GB 046313724b7a
model-layer-064.safetensorsWeights3.8 GB 619bda2b5b2c
model-layer-065.safetensorsWeights3.8 GB dd4e03fcf82e
model-layer-066.safetensorsWeights3.8 GB d063707e10c5
model-layer-067.safetensorsWeights3.8 GB 0cc9298f6553
model-layer-068.safetensorsWeights3.8 GB f451e3795fb0
model-layer-069.safetensorsWeights3.8 GB b544e8ac5604
model-layer-070.safetensorsWeights3.8 GB 237cf131c1d6
model-layer-071.safetensorsWeights3.8 GB 66fa9c354dbf
model-layer-072.safetensorsWeights3.8 GB 8cc0a329e273
model-layer-073.safetensorsWeights3.8 GB 092da8c11cb6
model-layer-074.safetensorsWeights3.8 GB e1111976a289
model-layer-075.safetensorsWeights3.8 GB 0f1968bdb00f
model-layer-076.safetensorsWeights3.8 GB 0f82ff0a7bbc
model-layer-077.safetensorsWeights3.8 GB 028cbc461962
model-layer-078.safetensorsWeights3.8 GB d02fc71e10a9
model-layer-079.safetensorsWeights3.8 GB 7b5e3a66728c
model-layer-080.safetensorsWeights3.8 GB 15242ece1a31
model-layer-081.safetensorsWeights3.8 GB 1a2a8d91b2a4
model-layer-082.safetensorsWeights3.8 GB 6860342a10ce
model-layer-083.safetensorsWeights3.8 GB 831477b5b973
model-layer-084.safetensorsWeights3.8 GB 06e443328384
model-layer-085.safetensorsWeights3.8 GB ce67ad4adb80
model-layer-086.safetensorsWeights3.8 GB 57284449eb59
model-layer-087.safetensorsWeights3.8 GB 809bdb952bef
model-layer-088.safetensorsWeights13.5 GB 24c0cef80ba0
model-layer-089.safetensorsWeights13.5 GB ae98298dbf92
model-layer-090.safetensorsWeights13.5 GB 178ae778101f
model-layer-091.safetensorsWeights592.2 MB 1cfb4c3077c3
model-vit-000.safetensorsWeights4.0 GB 3bb6e44845d1
config.jsonConfiguration36.6 KB —
csf-report.jsonConfiguration57.4 KB —
hf_quant_config.jsonConfiguration24.6 KB —
model.safetensors.index.jsonConfiguration315.5 KB —
special_tokens_map.jsonConfiguration468 B —
tools/convert_step5_csf.pyConfiguration13.8 KB —
LICENSE-CN.txtDocumentation6.5 KB —
LICENSE.txtDocumentation7.6 KB —
README.mdDocumentation9.5 KB —
SHA256SUMSOther9.9 KB —
chat_template.jinjaOther6.0 KB —
.gitattributesRepository1.5 KB —
tokenizer.jsonTokenizer10.0 MB —
tokenizer_config.jsonTokenizer163.4 KB —

License and Download

License
other
Access
Open weights, no gate
Download size
377.0 GB
Download from Brandon Music

Released by Brandon Music through its official repository on Hugging Face. Read the license.

Built From

  • Derived from stepfun-ai/Step-5-Preview-NVFP4
  • Quantized from stepfun-ai/Step-5-Preview-NVFP4

Evaluations

Each result is shown as reported, with the conditions its reporter stated. None is a SAVRN measurement. A comparison lines two results up only when their configuration, unit and setup are all stated and identical.

BenchmarkConditionsResultReported byRevisionDate
all 3,214 source tensors; the 255 routed-expert scale tensors (35,295,068,160 scale bytes) decoded and compared byte… Task Checkpoint identity vs stepfun-ai/Step-5-Preview-NVFP4 (lossless scale…Metric Fraction of other source tensors byte-identical in this…Comparison conditions not established 1 brandonmusic
Publisher reported
Evaluated revision not stated —
all 3,214 source tensors; the 255 routed-expert scale tensors (35,295,068,160 scale bytes) decoded and compared byte… Task Checkpoint identity vs stepfun-ai/Step-5-Preview-NVFP4 (lossless scale…Metric Fraction of source scale bytes reproduced exactly by…Comparison conditions not established 1 brandonmusic
Publisher reported
Evaluated revision not stated —

Memory Requirements

PrecisionWeights in memory
As published377.0 GB
16-bit677.1 GB
8-bit338.5 GB
4-bit169.3 GB

Weights only, from the published parameter count; the key-value cache and runtime add to this.

Questions About Step-5-Preview-NVFP4-Local

How much GPU memory does Step-5-Preview-NVFP4-Local need?

About 812.5 GB at 16-bit and 203.1 GB at 4-bit: the weights (338.5B parameters) plus a working margin. A long context needs more.

What is the cheapest GPU to run Step-5-Preview-NVFP4-Local on?

At 16-bit, 3x MI355X from $7.77 an hour; at 4-bit, 1x MI325X from $2.00 an hour, at the lowest on-demand prices the SAVRN Index lists.

What license is Step-5-Preview-NVFP4-Local released under?

other, as its publisher declares it. Read the license text before commercial use.

What is Step-5-Preview-NVFP4-Local's context length?

1,048,576 tokens, from the maximum position embeddings in its published configuration.

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