text model · llama · iOS
Can I run Llama 3.1 8B on iPhone 15 Pro?
No. Llama 3.1 8B needs ~6.4 GB even at Q4_K_M, but iPhone 15 Pro only has ~4.5 GB usable.
Needs ~6.4 GB even at Q4_K_M, but only ~4.5 GB is usable.
- Q4_K_M needed
- ~6.4 GB
- Usable on device
- ~4.5 GB
- Device memory
- 8 GB
How to run it
On iOS use Apple Foundation Models (Built into iOS 26, ~3B on-device model, zero download, fully private.). Phones realistically run 1B-4B class models. Anything larger thermally throttles or OOMs.
- Parameters
- 8B
- Q4_K_M size
- 4.92 GB
- Q8_0 size
- 8.54 GB
- Context
- 128k
- Ollama tag
- llama3.1:8b
- Memory
- 8 GB unified
- Usable for weights
- ~4.5 GB
- Best runtime
- llama.cpp + Metal (via PocketPal or Off Grid app)
What you can run instead
Run Llama 3.1 8B on other hardware
FAQ
Can iPhone 15 Pro run Llama 3.1 8B?
No. Llama 3.1 8B needs ~6.4 GB even at Q4_K_M, but iPhone 15 Pro only has ~4.5 GB usable.
How much memory does Llama 3.1 8B need?
iPhone 15 Pro does not have enough memory. At Q4_K_M the weights are ~4.92 GB; with KV cache and runtime overhead, budget ~6.4 GB at a 4k context.
What is the best tool to run Llama 3.1 8B 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.
Sources
Memory figures are estimates. See methodology.