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macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

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Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#101
post #68

George Hotz made nvidia running on macs with his tinygrad via usb4 https://x.com/__tinygrad__/status/1980082660920918045

https://social.treehouse.systems/@janne/115509948515319437 nvidia on a 2023 Mac Pro running linux :p

Geohotz stuff anyone can run today

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#102
post #66

Earlier quoted context omitted.

It’s just depressing that the “PC in every home” era is being rapidly pulled out from under our feet by all these supply shocks.

Huh? Home PCs are as cheap as they’ve ever been. Adjusted for inflation the same can be said about “home use” Macs. The list price of an entry level MacBook Air has been pretty much the same for more than a decade. Adjust for inflation, and you get a MacBook air for less than half the real cost of the launch model that is massively better in every way. A blip in high end RAM prices has no bearing on affordable home c…

  A blip in high end RAM prices 
It's not a blip and it's not limited to high end machines and configurations. Altman gobbled up the lion's share of wafer production. Look at that Raspberry Pi article that made it to the front page, that's pretty far from a high end Mac and according to the article's author likely to be exported from China due to the RAM supply crisis.

  I can get a Ryzen 7 system with 32gb of ddr5, and a 1tb drive delivered to my house
  before dinner tomorrow for $500 + tax.

B&H is showing a 7700X at $250 with their cheapest 32GB DDR5 5200 sticks at $384. So you've already gone over budget for just the memory and CPU. No motherboard, no SSD.

Amazon is showing some no-name stuff at $298 as their cheapest memory and a Ryzen 7700X at $246.

Add another $100 for an NVMe drive and another $70–100 for the cheapest AM5 motherboards I could find on either of those sites.

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#103
post #30

Earlier quoted context omitted.

I’m hoping this isn’t as attractive as it sounds for non-hobbyists because the performance won’t scale well to parallel workloads or even context processing, where parallelism can be better used. Hopefully this makes it really nice for people that want the experiment with LLMs and have a local model but means well funded companies won’t have any reason to grab them all vs GPUs.

The lack of official Linux/BSD support is enough to make it DOA for any serious large-scale deployment. Until Apple figures out what they're doing on that front, you've got nothing to worry about.

Not sure I understand, Mac OS is BSD based. https://en.wikipedia.org/wiki/Darwin_(operating_system)

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#104
post #87

Earlier quoted context omitted.

For $50K, you could buy 25 Framework desktop motherboards (128G VRAM each w/Strix Halo, so over 3TB total) Not sure how you'll cluster all of them but it might be fun to try. ;)

There is no way to achieve a high throughput low latency connection between 25 Strix Halo systems. After accounting for storage and network, there are barely any PCIe lanes left to link two of them together. You might be able to use USB4 but unsure how the latency is for that.

Do they need fast storage, in this application? Their OS could be on some old SATA drive or whatever. The whole goal is to get them on a fast network together; the models could be stored on some network filesystem as well, right?

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#105
post #89

dang I wish I could share md tables. Here’s a text edition: For $50k the inference hardware market forces a trade-off between capacity and throughput: * Apple M3 Ultra Cluster ($50k): Maximizes capacity (3TB). It is the only option in this price class capable of running 3T+ parameter models (e.g., Kimi k2), albeit at low speeds (~15 t/s). * NVIDIA RTX 6000 Workstation ($50k): Maximizes throughput (>80 t/s). It is sup…

What's the math on the $50k nvidia cluster? My understanding these things cost ~$8k and you can at least get 5 for $40k, that's around half a tb. That being said, for inference mac still remain the best, and the M5 Ultra will even be a better value with its better PP.

GPUs: 4x NVIDIA RTX 6000 Blackwell (96GB VRAM each) • Cost: 4 × $9,000 = $36,000

• CPU: AMD Ryzen Threadripper PRO 7995WX (96-Core) • Cost: $10,000

• Motherboard: WRX90 Chipset (supports 7x PCIe Gen5 slots) • Cost: $1,200

• RAM: 512GB DDR5 ECC Registered • Cost: $2,000

• Chassis & Power: Supermicro or specialized Workstation case + 2x 1600W PSUs. • Cost: $1,500

• Total Cost: ~$50,700

It’s a bit maximalist, but if you had to spend $50k it’s going to be about as fast as you can make it.

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#106

dang I wish I could share md tables. Here’s a text edition: For $50k the inference hardware market forces a trade-off between capacity and throughput: * Apple M3 Ultra Cluster ($50k): Maximizes capacity (3TB). It is the only option in this price class capable of running 3T+ parameter models (e.g., Kimi k2), albeit at low speeds (~15 t/s). * NVIDIA RTX 6000 Workstation ($50k): Maximizes throughput (>80 t/s). It is sup…

Apple deploys LPDDR5X for the energy efficiency and cost (lower is better), whereas NVIDIA will always prefer GDDR and HBM for performance and cost (higher is better).

the GH/GB compute has LPDDR5X - a single or dual GPU shares 480GB, depending if it's GH or GB, in addition to the HBM memory, with NVLink C2C - it's not bad!

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#107

Apple should setup their own giant cloud of M chips with tons of vram, make Metal as good as possible for AI purposes, then market the cloud as allowing self-hosted models for companies and individuals that care about privacy. They would clean up in all kinds of sectors whose data can't touch the big LLM companies.

That exists but it's only for iUsers running Apple models. https://security.apple.com/blog/private-cloud-compute/

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#108
post #3

I follow the MLX team on Twitter and they sometimes post about using MLX on two or more joined together Macs to run models that need more than 512GB of RAM. A couple of examples: Kimi K2 Thinking (1 trillion parameters): https://x.com/awnihannun/status/1986601104130646266 DeepSeek R1 (671B): https://x.com/awnihannun/status/1881915166922863045 - that one came with setup instructions in a Gist: https://gist.github.com/…

For a bit more context, those posts are using pipeline parallelism. For N machines put the first L/N layers on machine 1, next L/N layers on machine 2, etc. With pipeline parallelism you don't get a speedup over one machine - it just buys you the ability to use larger models than you can fit on a single machine. The release in Tahoe 26.2 will enable us to do fast tensor parallelism in MLX. Each layer of the model is…

> The main challenge is latency since you have to do much more frequent communication.

Earlier this year I experimented with building a cluster to do tensor parallelism across large cache CPUs (AMD EPYC 7773X have 768mb of L3). My thought was to keep an entire model in SRAM and take advantage of the crazy memory bandwidth between CPU cores and their cache, and use Infiniband between nodes for the scatter/gather operations.

Turns out the sum of intra-core latency and PCIe latency absolutely dominate. The Infiniband fabric is damn fast once you get data to it, but getting it there quickly is a struggle. CXL would help but I didn't have the budget for newer hardware. Perhaps modern Apple hardware is better for this than x86 stuff.

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#109

Apple should setup their own giant cloud of M chips with tons of vram, make Metal as good as possible for AI purposes, then market the cloud as allowing self-hosted models for companies and individuals that care about privacy. They would clean up in all kinds of sectors whose data can't touch the big LLM companies.

The advantages of having a single big memory per gpu are not as big in a data center where you can just shard things between machines and use the very fast interconnect, saturating the much faster compute cores of a non Apple GPU from Nvidia or AMD

Re: macOS 26.2 enables fast AI clusters with RDMA over Thunderbolt

#110
post #66

Earlier quoted context omitted.

It’s just depressing that the “PC in every home” era is being rapidly pulled out from under our feet by all these supply shocks.

Huh? Home PCs are as cheap as they’ve ever been. Adjusted for inflation the same can be said about “home use” Macs. The list price of an entry level MacBook Air has been pretty much the same for more than a decade. Adjust for inflation, and you get a MacBook air for less than half the real cost of the launch model that is massively better in every way. A blip in high end RAM prices has no bearing on affordable home c…

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