Hybrid-Phi-Mamba-1.5B

Closed weights Carnegie Mellon University (CMU),Mohamed bin Zayed University of Artificial Intelligence (MBZUAI),Cartesia 1.5B parameters August 2024

No estimate

No hardware requirements for this model

The weights for this model have not been published, so it cannot be downloaded or run on your own hardware at any size. It is reachable only through its provider, and no graphics card changes that.

On record

Full specification

Everything on record for this model. Most of it describes how it was trained rather than how it runs — useful context for judging how much work went into it, and how it compares with models built at a different scale.

Origin

Who built this model, where, and when it was published.

Organisation
Carnegie Mellon University (CMU),Mohamed bin Zayed University of Artificial Intelligence (MBZUAI),Cartesia
Organisation type
Academia,Academia,Industry
Country
United States of America, United Arab Emirates
Published
19 August 2024
Authors
Aviv Bick, Kevin Y. Li, Eric P. Xing, J. Zico Kolter, Albert Gu

What it does

The problem areas the model was built for. A model can carry several of each.

Domain
Language
Task
Language modeling/generation
Base model
Phi-1.5

Size

How large the model is and how much data it was trained on. Parameters are the figure that decides whether it fits on a given graphics card.

Parameters
1.5B

"We distill the Phi-1.5-1.3B model into Phi-Mamba1.5B as well as Hybrid-Phi-Mamba-1.5B" (https://arxiv.org/pdf/2408.10189, page 8).

Training data
5,000,000,000 tokens

"The Hybrid-PhiMamba-1.5B is distilled on a budget of 5 billion tokens from the same dataset."

Training compute

The arithmetic performed to train the model, measured in floating-point operations. It is a measure of what the training run cost, not of how fast the finished model answers you.

Training compute
1.2 × 10²¹ FLOP

1.17e+21 FLOP [base model compute] + 4.5e+19 FLOP [finetune compute] = 1.215e+21 FLOP

How it was established
Operation counting
Fine-tuning compute
4.5 × 10¹⁹ FLOP

6 FLOP / parameter / token * 1.5 * 10^9 parameters * 5 * 10^9 tokens = 4.5e+19 FLOP

Availability

Whether you can obtain the model and run it on your own hardware, which is what decides if any of the graphics-card figures on this page apply.

Weights
Closed — provider access only
Model access
Unreleased
Training code
Unreleased

How it is classified

Labels the source dataset applies when tracking notable models, and how confident it is in the entry.

Record confidence
Confident

Sources

Where this record came from and when it was last checked.

Reference
Transformers to SSMs: Distilling Quadratic Knowledge to Subquadratic Models
Last updated
28 November 2025

What the numbers mean

Where it came from

Hybrid-Phi-Mamba-1.5B was published by Carnegie Mellon University (CMU),Mohamed bin Zayed University of Artificial Intelligence (MBZUAI),Cartesia, in United States of America, in August 2024. academia,Academia,Industry is the category the publisher falls under.

It works in Language, and is recorded as doing language modeling/generation.

Its starting point was Phi-1.5 — most models at this scale are adapted from an existing base rather than built from nothing.

Because the weights are not available, none of the hardware figures elsewhere on this site apply to it.

Training and provenance

Training it took roughly 1.2 × 10²¹ FLOP of computation — a measure of what producing the model cost, not of how fast it answers.

The training set ran to roughly 5,000,000,000 tokens.

Answers

Hybrid-Phi-Mamba-1.5B — common questions

01

How much compute was used to train Hybrid-Phi-Mamba-1.5B?

Around 1.2 × 10²¹ FLOP. That measures what producing the model cost and says nothing about how quickly it answers once trained — inference speed comes from memory bandwidth, not from the training budget.

02

What GPU do I need to run Hybrid-Phi-Mamba-1.5B?

None. Hybrid-Phi-Mamba-1.5B is a closed model — its weights were never published, so it cannot be downloaded or run on your own hardware at any price. It is reachable only through its provider.

03

Is Hybrid-Phi-Mamba-1.5B open source?

No. Hybrid-Phi-Mamba-1.5B has not had its weights published, so it exists only as a service controlled by its owner.

04

How many parameters does Hybrid-Phi-Mamba-1.5B have?

Hybrid-Phi-Mamba-1.5B has 1.5B parameters. "We distill the Phi-1.5-1.3B model into Phi-Mamba1.5B as well as Hybrid-Phi-Mamba-1.5B" (https://arxiv.org/pdf/2408.10189, page 8). That figure is the total, and it is what decides how much memory the model needs — roughly half a gigabyte per billion at the compression most people use.

05

Who created Hybrid-Phi-Mamba-1.5B?

Hybrid-Phi-Mamba-1.5B was published by Carnegie Mellon University (CMU),Mohamed bin Zayed University of Artificial Intelligence (MBZUAI),Cartesia, based in United States of America, categorised as academia,Academia,Industry.

06

When was Hybrid-Phi-Mamba-1.5B released?

Hybrid-Phi-Mamba-1.5B was published in August 2024. Capability per parameter has improved considerably since, so a newer model of the same size is often the better use of the same hardware.

07

What is Hybrid-Phi-Mamba-1.5B used for?

Hybrid-Phi-Mamba-1.5B works in Language, and is recorded as handling language modeling/generation. These are the areas it was designed around; they describe intent rather than a hard boundary.

Source

Original publication

Record last updated 28 November 2025

The other direction

Looking at it from the other side?

This page starts from the model. If you already own a card and want to know everything it will run, start from the hardware instead.