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Kimi K3 Architecture Overview and Notes

472 pointsby ModelForgeyesterday at 3:48 PM101 commentsview on HN

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Gihotoday at 10:12 AM

I wonder if Kimis KDA architecture is a way closer to online models(models that learn during interference).As KDA updates its state matrix: St =St−1 +βt (vt −St−1 kt )ktT

The expression (vt −St−1 kt )ktT is literally the gradient step of a linear regression model updating its weights (S) on a single sample using Mean Squared Error loss.

Interesting what other labs comes up with from this.

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mickael-kerjeantoday at 12:51 AM

Genuine question: how reproducible / usable / verifiable are these architectures from the published documentation? Are they similar to PDF/DWG/PSD specifications, where the format look like an open spec at first sight until you attempt to implement it and realize the crucial implementation details are undocumented?

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thatsgcaseyyesterday at 7:48 PM

Sabastian Raschka is one of the great LLM researchers/authors. I highly recommend his substack

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augment_metoday at 2:24 AM

I feel like the Kimi team is amongst the best in the industry to pick and choose what is meaningful from the other models. For example, avoiding the expensive and empirically uncertain mHC in favor of simpler residuals. Latent MoE.

My only doubts are around Linear Attention instead of DSA as this is inherently lossy. You are kind of banking on that your query is inherently in the embedding space of the model already and can be lossy.

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madhu_ghalametoday at 9:09 AM

A few diagrams showing how the data flows through the architecture would make these concepts much easier to grasp.

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gbosstoday at 4:09 AM

Anybody getting the result that Kimi 3 is more expensive than Opus 5 or Sol on Cursor? Pretty sure Kimi 3 sucked up a good chunk of my ultimate plan in a few prompts. Anyone have any tools or ways to understand per model usage towards cursor subscriptions? I know there are alternatives to cursor just haven’t made the move yet. (Edit spelling)

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Ilaurensyesterday at 8:49 PM

"Interestingly, Kimi K3 got rid of all RoPE layers and uses NoPE (No Positional Embeddings) everywhere instead."

It just baffles me that this even works at all. Doesn't it just become a token soup? Is attention that precise that a second token can tell its the second token just because it learns to accumulate something in the embedding space without any sort of inductive bias?

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doolstoday at 9:26 AM

They may have all this amazing architecture but Kimi has been super dumb recently. I reckon they’re under compute pressure and quantising to stay afloat. I was a heavy k2.5/2.6 user earlier in the year and built serious features with it, but even k3 now does stupid shit like fail tool calls and get stuck in endless thought trains. K2.6 was spinning its wheels on a problem for over 10 minutes today and then deepseek v4 fixed it in under a minute.

Something is wrong at moonshot.

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rglovertoday at 12:18 AM

Just tried K3 out for the first time today and it's a legitimate threat.

Temporarily (maybe permanently) using it as my daily driver but it's wild how comparable it is to Opus 4.7/4.8 (what's been my go to for a bit now—wrote a quick post on what I found today [1]).

[1] https://graybearding.bearblog.dev/kimi-k3-is-insane/

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constantlmyesterday at 9:47 PM

So, unlike what leaders of western labs labs would like you to believe (that Kimi is just the result of distillation attacks), they are introducing new and novel approaches.

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rekperotoday at 9:12 AM

kimi K3 felt on par with my claude opus 4.8 in my first tests and is exceptionally good at frontend and website motion design, but I still find it hard to switch back and forth between claude and kimi, and i’m not sure if others are experiencing the same thing.

alealvarezargyesterday at 7:28 PM

Great breakdown. After using Kimi extensively, it's fascinating to see how architectural choices like KDA and NoPE translate into such strong real-world performance. Really impressive engineering.

souravsspaceyesterday at 8:00 PM

i like your detailed breakdown. Thanks. <3

RobLachyesterday at 9:52 PM

Concise. Nice.

TokenLattoday at 8:02 AM

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gokohlyesterday at 4:56 PM

Interesting that they went NoPE everywhere — everyone else hedges with RoPE in the local layers. Feels like the linear-attention stuff (Kimi Delta) is quietly doing the positional work so they can get away with it. Curious to see if it holds up at frontier scale.

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jartan2002today at 12:27 AM

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myronkeir1968yesterday at 8:56 PM

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myronkeir1968yesterday at 8:55 PM

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pullrunyesterday at 8:55 PM

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dumpstertechopsyesterday at 9:27 PM

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