A developer on r/LocalLLaMA wanted to run a 27B parameter model on an M4 Pro MacBook Pro.
It fit, barely.
Then the 24GB of unified memory became the wall.
The context window capped at 64K, and prefill speeds sagged the moment the model needed room to think.
His fix was not a bigger machine.
He plugged an iPhone 17 Pro Max into the Mac over USB-C and split the work.
The Mac ran layers 1 through 40 of each batch and streamed activations to the phone.
The iPhone ran layers 41 through 64 on its A19 Pro GPU while the Mac started the next batch.
The numbers moved.
Prefill at 8K context went from 132 to 177 tokens per second.
At 16K it went from 109 to 157, a 44 percent gain.
At 32K it went from 101 to 130.
Ingenious.
Also a symptom.
When one 27B model needs a phone as a second GPU, the compute bill is shaping the architecture.
That is the wall BHK Cloud removes.
RTX 3090 compute at $0.15/hr, the best price on the market, with Buy Now Pay Later so you start at zero upfront and pay after one month.
What is the largest model you have run on hardware it was never designed for?
https://ai.bhkcloud.com/?utm_source=linkedin&utm_medium=social&utm_campaign=bhk_social_2026w40&utm_content=evening
Originally posted on linkedin_personal