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iPhone 17 Pro Demonstrated Running a 400B LLM

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Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#172
post #9

Earlier quoted context omitted.

Looks like it's Qwen3.5-397B-A17B so 17B active. https://github.com/Anemll/flash-moe/tree/iOS-App

Stupid question: can i run this on my 64GB/1TB mac somehow easily? Or this requires custom coding? 4bit is ~200GB EDIT: found this in the replies: https://github.com/Anemll/flash-moe/tree/iOS-App

Yes, SSD speed is critical though. The repo has macOS builds for CLI and Desktop. It's early stages though. M4 Max gets 10-15 TPS on 400B depending on quantization. Compute is an issue too; a lot of code is PoC level.

Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#173

I can't understand why this is a surprise to anyone. An iphone is still a computer, of course it can run any model that fits in storage albiet very slowly. The implementation is impressive I guess but I don't see how this is a novel capability. And for 0.6t/s, its not a cost efficient hardware for doing it. The iphone can also render pixar movies if you let it run long enough, mine bitcoin with a pathetic hashrate, a…

SSD streaming to compute units is new. M4 max can do 15 t/s with its 15GB/s drives

Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#174

Earlier quoted context omitted.

Running larger-than-RAM LLMs is an interesting trick, but it's not practical. The output would be extremely slow and your computer would be burning a lot of power to get there. The heavy quantizations and other tricks (like reducing the number of active experts) used in these demos severely degrade the quality. With 64GB of RAM you should look into Qwen3.5-27B or Qwen3.5-35B-A3B. I suggest Q5 quantization at most fro…

I've tried a number of experiments, and agree completely. If it doesn't fit in RAM, it's so slow as to be impractical and almost useless. If you're running things overnight, then maybe, but expect to wait a very long time for any answers.

Current local-AI frameworks do a bad job of supporting the doesn't-fit-in-RAM case, though. Especially when running combined CPU+GPU inference. If you aren't very careful about how you run these experiments, the framework loads all weights from disk into RAM only for the OS to swap them all out (instead of mmap-ing the weights in from an existing file, or doing something morally equivalent as with the original MacBook Pro experiment) which is quite wasteful!

This approach also makes less sense for discrete GPUs where VRAM is quite fast but scarce, and the GPU's PCIe link is a key bottleneck. I suppose it starts to make sense again once you're running the expert layers with CPU+RAM.

Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#175

[flagged]

This has a simple pragmatic solution though: https://duckdb.org/2024/12/06/duckdb-tpch-sf100-on-mobile#a-...

From the same article:

"The phone a few minutes after finishing the benchmark. It no longer booted because the battery was too cold!"

Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#176
post #63
post #23

This is awesome! How far away are we from a model of this capability level running at 100 t/s? It's unclear to me if we'll see it from miniaturization first or from hardware gains

Probably 15 to 20 years, if ever. This phone is only running this model in the technical sense of running, but not in a practical sense. Ignore the 0.4tk/s, that's nothing. What's really makes this example bullshit is the fact that there is no way the phone has a enough ram to hold any reasonable amount of context for that model. Context requirements are not insignificant, and as the context grows, the speed of the o…

> Realistically you need +300GB/s fast access memory to the accelerator, with enough memory to fully hold at least greater than 4bit quants.

The latest M5 MacBook Pro's start at 307 GB/s memory bandwidth, the 32-core GPU M5 Max gets 460 GB/s, and the 40-core M5 Max gets 614 GB/s. The CPU, GPU, and Neural Engine all share the memory.

The A19/A19 Pro in the current iPhone 17 line is essentially the same processor (minus the laptop and desktop features that aren’t needed for a phone), so it would seem we're not that far off from being able to run sophisticated AI models on a phone.

Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#177

[flagged]

This has a simple pragmatic solution though: https://duckdb.org/2024/12/06/duckdb-tpch-sf100-on-mobile#a-...

It takes a particularly dry and cool-as-ice sense of humor to label this solution a "simple" and "pragmatic" one.

Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#178
post #10

> SSD streaming to GPU Is this solution based on what Apple describes in their 2023 paper 'LLM in a flash' [1]? 1: https://arxiv.org/abs/2312.11514

Yes. I collected some details here: https://simonwillison.net/2026/Mar/18/llm-in-a-flash/

Thanks for posting this, that's how I first found out about Dan's experiment! SSD speed doubled in the M5P/M generation, that makes it usable! I think one paper under the radar is "KV Prediction for Improved Time to First Token" https://arxiv.org/abs/2410.08391 which hopefully can help with prefill for Flash streaming.

Re: iPhone 17 Pro Demonstrated Running a 400B LLM

#179
post #65

Earlier quoted context omitted.

That's actually pretty cool, but I'd hate to freeze a models weights into silicon without having an incredibly specific and broad usecase.

Sounds like just the sort of thing FGPA's were made for. The $$$ would probably make my eyes bleed tho.

Wouldn't it be the opposite of freezing weights?
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