text model · gpt-oss · iOS

Can I run gpt-oss 120B on iPhone 17?

Compatibility verdict VRAM threshold engine

No, not enough memory would not load

No. gpt-oss 120B needs ~62.4 GB even at Q4_K_M, but iPhone 17 only has ~4.5 GB usable.

Needs ~62.4 GB Device usable ~4.5 GB

Needs ~62.4 GB even at Q4_K_M, but only ~4.5 GB is usable.

That figure is at a 4k context and moves about ±15% as context length changes.

The gap is about 57.9 GB: gpt-oss 120B needs roughly 62.4 GB at Q4_K_M and iPhone 17 leaves only about 4.5 GB usable for a model. The lightest tracked hardware that runs gpt-oss 120B is the Apple M4 Max (128GB) at 128 GB. See gpt-oss 120B on Apple M4 Max (128GB).

Q4_K_M needed: ~62.4 GB
Usable on device: ~4.5 GB
Device memory: 8 GB

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Which quant fits

Quant ladder vs ~4.5 GB usable

Q2_K

~52.4 GB

Q3_K_M

~60.6 GB

Q4_K_M

~62.4 GB

Q5_K_M

~86.8 GB

Q6_K

~99.3 GB

Q8_0

~4.2 GB

FP16

~237.4 GB

The line marks iPhone 17's ~4.5 GB budget; rungs past it are too large.

How to run it

On iOS use Apple Foundation Models (Built into iOS 26, ~3B on-device model, zero download, fully private.).

Model gpt-oss

Parameters: 117B (MoE, 5.1B active)
Q4_K_M size: 59.03 GB
Q8_0 size: 0.79 GB
Context: 128k
Ollama tag: gpt-oss:120b

Full gpt-oss 120B requirements →

Device iOS

Memory: 8 GB unified
Usable for weights: ~4.5 GB
Best runtime: llama.cpp + Metal (via PocketPal or Off Grid app)

Best models for iPhone 17 →

What you can run instead

Run gpt-oss 120B on other hardware

Apple M4 Max (128GB)AMD Ryzen AI Halo (128GB)Apple M5 Max (128GB)Apple M3 Ultra (256GB)

FAQ

Can iPhone 17 run gpt-oss 120B?

No. gpt-oss 120B needs ~62.4 GB even at Q4_K_M, but iPhone 17 only has ~4.5 GB usable.

How much memory does gpt-oss 120B need?

iPhone 17 does not have enough memory. At Q4_K_M the weights are ~59.03 GB; with KV cache and runtime overhead, budget ~62.4 GB at a 4k context. It is a Mixture-of-Experts model (117B total / 5.1B active), so all experts must stay in memory; memory tracks total params, not active params.

What is the best tool to run gpt-oss 120B on iOS?

On iPhone and iPad, Apple Foundation Models (Built into iOS 26, ~3B on-device model, zero download, fully private.) is the standard choice. Phones realistically run 1B-4B class models. Anything larger thermally throttles or OOMs.

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Markdown

[![gpt-oss 120B on iPhone 17](https://localmodel.run/badge/gpt-oss-120b/iphone-17.svg)](https://localmodel.run/can-i-run/gpt-oss-120b/iphone-17)

Sources

Weights are measured from GGUF files; KV cache and overhead are computed, so totals can vary ~15% with context and runtime. Any tok/s is a bandwidth estimate. See methodology.