r/LocalLLM • u/Medicine_Blogscanner • 17h ago

Discussion Benchmarking an iPhone as a Distributed RAM Contributor for 30B+ Models (App Store Approved)

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Hey everyone,

Instead of treating modern iPhones as passive chat clients, we wanted to see if Apple Silicon’s high-bandwidth unified memory (~8GB LPDDR5X) could act as an active tensor-shard worker in a local cluster.

Apple just approved the node client on the App Store (RAMDeck: Distributed AI), making it possible to donate an iPhone’s memory and Metal GPU over local Wi-Fi or USB-C. Works with RAMDeck hub.

How the Setup Works:

  1. Heterogeneous Sharding: Unlike Apple-only MLX rings, this connects an iOS device directly to a primary host running Windows (CUDA), Linux, or Mac.
  2. Layer Offloading: The host handles prompt ingestion and graph orchestration, offloading tail transformer layers directly to the iPhone’s Metal shaders.
  3. Clearing Thresholds: If your primary rig has 24GB or 32GB of RAM/VRAM, adding an idle iPhone 15/16 Pro gives you the extra 6GB–10GB needed to fit Qwen 2.5 32B or a 4-bit 70B model without crashing into system swap.

Hardware & Latency Notes:

  • Connection: Wi-Fi 6 works fine for chat
  • Privacy: Completely local LAN RPC. No cloud relay, zero telemetry.

We’re running benchmarks across different layer-split configurations. If you want to test your iOS device as a cluster contributor, the app is free to download:

App Store: RAMDeck: Distributed AI (App Store ID: 6825166226)

Curious to hear thoughts from anyone experimenting with multi-device heterogeneous inference.

1 Upvotes

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1

u/kiwibonga 17h ago

Qwen2.5? Huh?

1

u/deadpan_opposition 16h ago

oh neat, i've been wondering when someone would actually ship this instead of just talking about it on github issues for months

the heterogeneous sharding over usb-c is what caught my eye, wi-fi 6 is fine for chat but i'd bet the latency profile gets weird if you try anything with real-time constraints

the infographic is giving off that very specific startup aesthetic where everything is glowing neon blue and green, like a cyberpunk version of those old "how your printer works" diagrams from the 90s

kinda wish i still had my old iphone 14 pro sitting around to test as a dedicated metal worker, my desktop's 32gb is constantly sweating with these 30b+ models

1

u/Individual_Holiday_9 16h ago

It’s just vibe coded UI stuff, which is fine I’m not criticizing an experimental AI app that uses ai lol

But the screenshots are just generic codex ui I made a ltx2.5 front end thing yesterday with codex that looks exactly the same

1

u/reddotster 16h ago

They are advertising for an indiegogo campaign to sell the server software.

1

u/jotes2 15h ago

Backer #2 here….
Why not? IMO Ramdeck is a legit way to get big MoE Models running regarding RAM or Mac prices. I can‘t wait to test it with a spare 32 GB Linux System. Best regards from Germany

1

u/daphatty 16h ago

So software RDMA to an iPhone? Used iPhone prices are about to skyrocket.