To the extent that the present LLM movement reaches a steady state conclusion it’s highly likely to be open source models on your own hardware that are “good enough” for 95% of use cases.
That blows up the whole “industrial complex” being developed around massive data centers, proprietary models, and everything that goes with that. Complete implosion.
Apple has sat on the sidelines for much of this as it seems clear they know the end game is everyone just does this stuff locally on their phone or computer and then it’s game over for everything going on now.
I had a dream that everyone had super intelligent AIs in their pockets, and yet all they did was doomscroll and catfish...shortly before everything was destroyed.
This is less about “running a 400B model on a phone” and more about clever engineering around constraints.
What’s actually happening is:
in mixture-of-experts only a small subset of weights is active per token
Aggressive quantization
Streaming weights from storage instead of loading everything into RAM
So the effective working set is much smaller than 400B.
That said, the trade-offs are obvious: very low token throughput, high latency, and heavy reliance on storage bandwidth. It’s more of a proof-of-concept than something usable.
Qwen3.5-397B-A17B behaves more like a 17B parameter model. Omitting the MoE part from the headline makes it a lie and stupid hype.
Quantizing is also a cheat code that makes the numbers lie, next up someone is going to claim running a large model when they're running a 1-bit quantization of it.
Incredible milestone. aiME's been running Qwen, Mistral, Gemma on iPhone since last year — even on older devices. Vision models, TTS/STT, all fully offline. One-time purchase, nothing ever leaves your phone. The hardware trajectory is wild. https://apps.apple.com/us/app/aime-ondevice-ai/id6754805828
I have some macro opinions about Apple - not sure if I'm correct, but tell me what you think.
Apple has always seen RAM as an economic advantage for their platform: Make the development effort to ensure that the OS and apps work well with minimal memory and save billions every year in hardware costs. In 2026, iPhones still come with 8Gb of RAM, Pro/Max come with 12Gb.
The problem is that AI (ML/LLM training and inference) are areas where you can't get around the need for copious amounts of fast working memory. (Thus the critical shortage of RAM at the moment as AI data centers consume as many memory chips as possible.)
Unless there's something I don't know (which is more than possible) Apple can't code their way around this problem, nor create specialized SoCs with ML cores that obviate the need for lots and lots of RAM.
So, it's going to be interesting whether they accept this reality and we start seeing the iPhones in the future with 16Gb, 32Gb or more as standard in order to make AI performant. And if they give up on adding AI to the billions of iPhones with minimal RAM already out there.
As a side note, 8Gb of RAM hasn't been enough for a decade. It prevents basic tasks like keeping web tabs live in the background. My pet peeve is having just a few websites open, and having the page refresh when swapping between them because of aggressive memory management.
To me, Apple's obvious strength is pushing AI to the edge as much as possible. While other companies are investing in massive data centers which will have millions of chips that will be outdated within the next couple years, Apple will be able to incrementally improve their ML/AI features by running on the latest and greatest chips every year. Apple has a huge advantage in that they can design their chips with a mega high speed bus, which is just as important as the quantity of RAM.
But all that depends on Apple's willingness to accept that RAM isn't an area they can skimp on any more, and I'm not sure they will.
Sorry for the brain dump. I'd love to be educated on this in case I'm totally off base.
It's a nice experiment, but I really wonder what's the use case? Privacy, yes. Local, yes. But then? Will people really use an LLM in their iPhone while they can use LLM infrastructure with bigger models for complex tasks? I mean, it really looks cool. But I don't think it's gonna be the future of local AI also. Maybe someone who can build up a very specialized local model for one particular task can enjoy that. Not sure it's gonna be massively use by the common of the mortals... But fore sure, for the industry, there is maybe a direction where we could have different very specialized models, on our devices, that could interoperate together, and then, provide something useful. We'll see. Interesting though! Maybe we still need some years, or decades, before we have devices, laptops, good enough to run good models.
I installed Termux on an old Android phone last week (running LineageOS), and then using Termux installed Ollama and a small model. It ran terribly, but it did run.
Don't get me wrong, it's an awesome achievement, but 0.6s token/s at presumably fairly heavy compute (and battery), on a mobile device? There aren't too many use cases for that :)
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
Qwen's MoE models are god awful when they are only running 2B parameters or whatever they downscale to while active. It isn't a 400B model if there's only several orders of magnitude less parameters active when you're actually inferencing...
Total gimmick. I guess we're "making progress", but this is will never lead to any useful application other than "Yes, you're absulotely right" bots. What's needed for real applications is 10000× the input token context and 10× the output token speed, so we're off by a factor of ... 100,000×?
Apple’s unified memory architecture plays a huge part in this. This will trigger a large scale rearchitecture of mobile hardware across the board. I am sure they are already underway.
I understand this is for a demo but do we really need a 400B model in the mobile? A 10B model would do fine right? What do we miss with a pared down one?
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, and do weather simulations but not in time for the forecast to be relevant.
The heat problem is going to be the real constraint here. I've been running smaller models locally for some internal tooling at work and even those make my MacBook sound like a jet engine after twenty minutes. A 400B model on a phone seems like a great way to turn your pocket into a hand warmer, even with MoE routing. The unified memory is clever but physics still applies.
Sometimes it looks like the purpose of those hundreds of billions of parameters and those apparent feats of engineering, is to get others to tell you how clever you are. Now we have even automated that.
It's crazy to see a 400B model running on an iPhone. But moving forward, as the information density and architectural efficiency of smaller models continue to increase, getting high-quality, real-time inference on mobile is going to become trivial.
iPhone 17 Pro Demonstrated Running a 400B LLM
(twitter.com)709 points by anemll 23 March 2026 | 327 comments
Comments
That blows up the whole “industrial complex” being developed around massive data centers, proprietary models, and everything that goes with that. Complete implosion.
Apple has sat on the sidelines for much of this as it seems clear they know the end game is everyone just does this stuff locally on their phone or computer and then it’s game over for everything going on now.
Is this solution based on what Apple describes in their 2023 paper 'LLM in a flash' [1]?
1: https://arxiv.org/abs/2312.11514
Quantizing is also a cheat code that makes the numbers lie, next up someone is going to claim running a large model when they're running a 1-bit quantization of it.
Apple has always seen RAM as an economic advantage for their platform: Make the development effort to ensure that the OS and apps work well with minimal memory and save billions every year in hardware costs. In 2026, iPhones still come with 8Gb of RAM, Pro/Max come with 12Gb.
The problem is that AI (ML/LLM training and inference) are areas where you can't get around the need for copious amounts of fast working memory. (Thus the critical shortage of RAM at the moment as AI data centers consume as many memory chips as possible.)
Unless there's something I don't know (which is more than possible) Apple can't code their way around this problem, nor create specialized SoCs with ML cores that obviate the need for lots and lots of RAM.
So, it's going to be interesting whether they accept this reality and we start seeing the iPhones in the future with 16Gb, 32Gb or more as standard in order to make AI performant. And if they give up on adding AI to the billions of iPhones with minimal RAM already out there.
As a side note, 8Gb of RAM hasn't been enough for a decade. It prevents basic tasks like keeping web tabs live in the background. My pet peeve is having just a few websites open, and having the page refresh when swapping between them because of aggressive memory management.
To me, Apple's obvious strength is pushing AI to the edge as much as possible. While other companies are investing in massive data centers which will have millions of chips that will be outdated within the next couple years, Apple will be able to incrementally improve their ML/AI features by running on the latest and greatest chips every year. Apple has a huge advantage in that they can design their chips with a mega high speed bus, which is just as important as the quantity of RAM.
But all that depends on Apple's willingness to accept that RAM isn't an area they can skimp on any more, and I'm not sure they will.
Sorry for the brain dump. I'd love to be educated on this in case I'm totally off base.
With all the money you will save on subscription fees you should be able to afford treatment for your psychosis!
Don't get me wrong, it's an awesome achievement, but 0.6s token/s at presumably fairly heavy compute (and battery), on a mobile device? There aren't too many use cases for that :)
This is a toy.
We need to build open infrastructure in the cloud capable of hosting a robust ecosystem of open weights.
And then we need to build very large scale open weights.
That's the only way we don't get owned by the hyperscalers.
At the edge isn't going to happen in a meaningful way to save us.
0.6 t/s, wait 30 seconds to see what these billions of calculations get us:
"That is a profound observation, and you are absolutely right ..."
With hardware and model improvements, the future is bright.
Local LLMs are going to make people sit on their phones instead of taking to real people.
Practical LLMs on mobile devices are at least a few years away.
I understand this is for a demo but do we really need a 400B model in the mobile? A 10B model would do fine right? What do we miss with a pared down one?
> That is a profound observation, and you are absolutely right
Twenty seconds and a hot phone for that.
In the end it took almost four minutes to generate under 150 tokens of nothing.
Impressive that they got it to run, but that’s about the only thing.