Model reference · open weights

Phi-3.5-MoE

LLMs microsoft Text gen · MoE 1 build Open weights 132k dl/mo

Phi-3.5-MoE is an open-weight language model from microsoft. Phi-3.5-MoE-instruct (BF16) weighs 83.7 GB; the smallest configuration that runs it is 4× RTX 4090 24 GB.

  • Phi-3.5-MoE is a multilingual text-generation model developed by Microsoft, designed for memory-constrained environments and strong reasoning in code, math, and logic.
  • The model features a mixture-of-experts architecture with 41.9B total parameters and 6.6B active parameters, supporting a 128K token context length.
  • It is released under the MIT license and was trained on 4.9 trillion tokens between April and August 2024.

Summary of the microsoft/Phi-3.5-MoE-instruct model card, 2026-10-01

What it is

Released bymicrosoft
Released2024-08-17
Parameters41.9B
VRAM83.7 GB for the weights

What it runs on

Memory and cards for Phi-3.5-MoE-instruct (BF16)

83.7 GBweights, file size
131 MBcache per 1K tokens
582 MBruntime overhead, at least
131,072 tokenscontext max
CardRequests at onceContext maxMemory
8K each32K each
RTX 3060 12 GB … H100 80 GB
8 smaller cards
———
RTX PRO 6000 Blackwell 96 GB6149K93.8 GB
DGX Spark (GB10) 128 GB unified184all 128K107 GB
H200 141 GB4711all 128K138 GB
B200 180 GB8220all 128K176 GB
4× RTX 4090 24 GB
tensor parallel
6154K23.4 GB a card
4× RTX 3090 24 GB
tensor parallel
7156K23.4 GB a card
4× RTX 5090 32 GB
tensor parallel
358all 128K31.0 GB a card
2× H100 80 GB
tensor parallel
6115all 128K78.1 GB a card
2× A100 80 GB
tensor parallel
6616all 128K78.2 GB a card
4× L40S 48 GB
tensor parallel
8320all 128K44.0 GB a card
2× RTX PRO 6000 Blackwell 96 GB
tensor parallel
9022all 128K93.8 GB a card
Memory needed at each load
Requests at once8K tokens each32K tokens each
185.4 GB88.6 GB
589.7 GB106 GB
892.9 GB119 GB
16102 GB153 GB
32119 GB222 GB
64153 GB359 GB

One card, with vLLM's small-card settings.

From the model card

What microsoft says about Phi-3.5-MoE

Read the model card

Model Summary

Phi-3.5-MoE is a lightweight, state-of-the-art open model built upon datasets used for Phi-3 - synthetic data and filtered publicly available documents - with a focus on very high-quality, reasoning dense data. The model supports multilingual and comes with 128K context length (in tokens). The model underwent a rigorous enhancement process, incorporating supervised fine-tuning, proximal policy optimization, and direct preference optimization to ensure precise instruction adherence and robust safety measures.

🏡 Phi-3 Portal 📰 Phi-3 Microsoft Blog 📖 Phi-3 Technical Report 👩‍🍳 Phi-3 Cookbook 🖥️ Try It

MoE references: 📜Phi-3.5-MoE Blog | 😁GRIN MoE

Phi-3.5: [mini-instruct]; [MoE-instruct] ; [vision-instruct]

Intended Uses

Primary Use Cases

The model is intended for commercial and research use in multiple languages. The model provides uses for general purpose AI systems and applications which require:

  1. Memory/compute constrained environments
  2. Latency bound scenarios
  3. Strong reasoning (especially code, math and logic)

Our model is designed to accelerate research on language and multimodal models, for use as a building block for generative AI powered features.

Use Case Considerations

Our models are not specifically designed or evaluated for all downstream purposes. Developers should consider common limitations of language models as they select use cases, and evaluate and mitigate for accuracy, safety, and fariness before using within a specific downstream use case, particularly for high risk scenarios. Developers should be aware of and adhere to applicable laws or regulations (including privacy, trade compliance laws, etc.) that are relevant to their use case.

Nothing contained in this Model Card should be interpreted as or deemed a restriction or modification to the license the model is released under.

Usage

Requirements

Phi-3.5-MoE-instruct is integrated in the official version of transformers starting from 4.46.0. The current transformers version can be verified with: pip list | grep transformers.

Examples of required packages:

flash_attn==2.5.8
torch==2.3.1
accelerate==0.31.0
transformers==4.46.0

Phi-3.5-MoE-instruct is also available in Azure AI Studio

Tokenizer

Phi-3.5-MoE-Instruct supports a vocabulary size of up to 32064 tokens. The tokenizer files already provide placeholder tokens that can be used for downstream fine-tuning, but they can also be extended up to the model's vocabulary size.

Input Formats

Given the nature of the training data, the Phi-3.5-MoE-instruct model is best suited for prompts using the chat format as follows:

You are a helpful assistant.
How to explain Internet for a medieval knight?

Loading the model locally

After obtaining the Phi-3.5-MoE-instruct model checkpoints, users can use this sample code for inference.

import torch
from transformers import AutoModelForCausalLM, AutoTokenizer, pipeline

torch.random.manual_seed(0)

model = AutoModelForCausalLM.from_pretrained(
    "microsoft/Phi-3.5-MoE-instruct",
    device_map="cuda",
    torch_dtype="auto",
    trust_remote_code=False,
)

tokenizer = AutoTokenizer.from_pretrained("microsoft/Phi-3.5-MoE-instruct")

messages = [
    {"role": "system", "content": "You are a helpful AI assistant."},
    {"role": "user", "content": "Can you provide ways to eat combinations of bananas and dragonfruits?"},
    {"role": "assistant", "content": "Sure! Here are some ways to eat bananas and dragonfruits together: 1. Banana and dragonfruit smoothie: Blend bananas and dragonfruits together with some milk and honey. 2. Banana and dragonfruit salad: Mix sliced bananas and dragonfruits together with some lemon juice and honey."},
    {"role": "user", "content": "What about solving an 2x + 3 = 7 equation?"},
]

pipe = pipeline(
    "text-generation",
    model=model,
    tokenizer=tokenizer,
)

generation_args = {
    "max_new_tokens": 500,
    "return_full_text": False,
    "temperature": 0.0,
    "do_sample": False,
}

output = pipe(messages, **generation_args)
print(output[0]['generated_text'])

Benchmarks

To understand the capabilities, we compare Phi-3.5-MoE with a set of models over a variety of benchmarks using our internal benchmark platform. At the high-level overview of the model quality on representative benchmarks:

CategoryBenchmarkPhi-3.5-MoE-instructMistral-Nemo-12B-instruct-2407Llama-3.1-8B-instructGemma-2-9b-ItGemini-1.5-FlashGPT-4o-mini-2024-07-18 (Chat)
Popular aggregated benchmarkArena Hard37.939.425.742.055.275.0
BigBench Hard CoT (0-shot)79.160.263.463.566.780.4
MMLU (5-shot)78.967.268.171.378.777.2
MMLU-Pro (0-shot, CoT)54.340.744.050.157.262.8
ReasoningARC Challenge (10-shot)91.084.883.189.892.893.5
BoolQ (2-shot)84.682.582.885.785.888.7
GPQA (0-shot, CoT)36.828.626.329.237.541.1
HellaSwag (5-shot)83.876.773.580.967.587.1
OpenBookQA (10-shot)89.684.484.889.689.090.0
PIQA (5-shot)88.683.581.283.787.588.7
Social IQA (5-shot)

Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.

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