Free guide · Oct 7, 2026
Use your iPhone to speed up local AI on your Mac
Set up Backburner with the right USB-C cable, install the free iPhone app, and connect it to your coding agent.
The short version
Backburner is a free, open source app that splits one big local AI model (Qwen3.8-27B) between your Mac and your iPhone over a USB-C cable. The Mac runs the first 40 layers, the phone runs the last 24 on its own GPU. Your Mac then reads long prompts and files faster, and it can hold more of the conversation at full quality.
What you need: an Apple Silicon Mac with 24 GB of memory or more, an iPhone 15 Pro or newer (a Pro model), a 10 Gb/s USB-C cable, a free Apple ID and about 24 GB of free disk space.
What to expect: faster reading, not faster writing. Answers come out at the same speed as the Mac alone below 64k tokens of context.
What's in the full guide
- 01Step 1: the free check before you download anything
- 02Step 2: get the right cable
- 03Step 3: install the free iPhone app
- 04Step 4: install the Mac side and send the phone its half
- 05Step 5: connect it to your coding agent
- 06Keep the app in front
- 07The honest limits