Arrakis / Models / phi-4

phi-4 GPU requirements

phi-4 has 15B parameters. To serve it, plan for about 35 GB of GPU memory in 16-bit, 18 GB in 8-bit or 8.8 GB in 4-bit, including about 20% for the KV cache and activations.

What it takes to serve it

GPU memory to run it for inference, with the smallest GPU setup that holds it and the lowest price on Arrakis right now.

PrecisionMemory and the smallest setup
16-bit35 GB: one L40S, RTX 6000 Ada or RTX A6000, L40S from $0.44 per GPU-hour
8-bit18 GB: one RTX 4090 or RTX 3090, RTX 3090 from $0.19 per GPU-hour
4-bit8.8 GB: one RTX 4090 or RTX 3090, RTX 3090 from $0.19 per GPU-hour

What it takes to fine-tune it

QLoRA trains adapters on a 4-bit frozen model, LoRA on a 16-bit one, and full fine-tuning updates every weight. Figures are before activations, which grow with batch size and sequence length.

MethodMemory and the smallest setup
QLoRA10 GB: one RTX 4090 or RTX 3090, RTX 3090 from $0.19 per GPU-hour
LoRA35 GB: one L40S, RTX 6000 Ada or RTX A6000, L40S from $0.44 per GPU-hour
Full fine-tuning235 GB: one B300, from $4.60 per GPU-hour

About the model

From its card and files on Hugging Face. Memory figures here follow the GPU memory guide.

Parameters
15B
Context window (tokens)
16,384
Published in
BF16
License
mit
Released
2024-12-11
Weights
microsoft/phi-4

Deploy it on Arrakis

Open Models in the console, choose vLLM, SGLang or llama.cpp, and rent a GPU it fits on. You get an OpenAI-compatible endpoint with its own API key, and root SSH to the machine. Or run it yourself on any machine with enough GPU memory:

vLLM
vllm serve microsoft/phi-4 --tensor-parallel-size 1

Questions

Live prices for every GPU are on the GPU prices page.

How much GPU memory does phi-4 need?
To serve it, about 35 GB in 16-bit, 18 GB in 8-bit, 9 GB in 4-bit, including about 20% for the KV cache and activations. To fine-tune it, about 10 GB with QLoRA, 35 GB with LoRA and 235 GB for full fine-tuning with Adam, before activations.
Can I run phi-4 on one GPU?
Yes. In 16-bit it needs about 35 GB, which fits on one L40S, RTX 6000 Ada or RTX A6000.
What does it cost to run phi-4?
In 16-bit it needs one L40S, RTX 6000 Ada or RTX A6000; in 4-bit, one RTX 4090 or RTX 3090. Each setup on this page shows the lowest price per GPU-hour on Arrakis right now, and you pay by the hour from a prepaid balance.
How do I deploy phi-4 on Arrakis?
Open Models in the Arrakis console, paste microsoft/phi-4, choose vLLM, SGLang or llama.cpp, and rent a GPU it fits on. You get an OpenAI-compatible endpoint with its own API key, and root SSH to the machine.