Marin 535B-A23B Starts Training, in the Open

2026-08-24T00:00:00+12:00

🚢 Marin 535B-A23B started training this week! As usual, the whole process is open.

Voyage plan: pretraining (80%) + midtraining (20%) on 18.75T tokens on 11 x GB200 NVL72 for ~3 months (2.7e24 FLOPs). Post-training will follow.

Before kicking off the run, we trained a 4-rung scaling ladder from 1.6B-A61M (48B tokens) to 27.7B-A1.2B (926B tokens) to debug issues, and to make a forecast of our hero run. This is by far our biggest run, so definitely expecting the unexpected.

Percy Liang, announcing the run on X.

The Marin project is a great example of being open to AI. The whole process is public: the scaling ladder they ran to debug the pipeline before committing GPU-months to the real thing, the exact token counts, the exact FLOPs, even the admission that they’re “expecting the unexpected” on their biggest run yet.

Most labs treat a run like this as a trade secret until the model ships. It’s great we see another public model build. The last public run at this scale was BLOOM, BigScience’s 176B model. Marin’s 535B total parameters (23B active) puts it well past that, the biggest public pretraining run that I’m aware of.

Pretraining a Mini Kimi K3 for $252

2026-08-21T00:00:00+12:00

Vizuara AI Labs trained a miniature Kimi K3 from scratch: 1.02B parameters, 145M active, 5B tokens, one H200, $252.35.

Not simplifying the architecture like Karpathy’s microgpt, they kept Kimi K3’s MoE and attention design intact.

That’s a surprisingly cheap way to learn pretraining (in real-world). They worked through expert collapse, data-mixing bugs, distributed-training bugs, kernels, and GPU utilization on a modern MoE architecture.

A few things worth noting:

5B tokens is probably too little for a 1B model. The authors agree the run was budget constrained. So the cheap cost might due to the training stopped early.
Beating GPT-2 isn’t particularly meaningful when Mini K3 has roughly 10× the parameters.
MoE at this scale is debatable. A smaller dense model trained on more tokens would likely be better if the goal was capability.

Ju Lin's AI Weblog: Pretraining

Marin 535B-A23B Starts Training, in the Open

Pretraining a Mini Kimi K3 for $252