Kimi K3 vs Grok 4.7
Should you write with Kimi K3 or Grok 4.7? On this page the only thing that changes is the model. Both wrote their own version of the scripts behind 10 of my What's AI videos, five drafts per script, and four judges (three LLM judges from three model families plus Jev, a typed judge from TypeSafe) scored every draft blind, with my finished script as the reference. Kimi K3 leads overall, 88.1 to 87.6. Their per-model Elo intervals overlap on this board.
The verdict
Kimi K3 is #21 and Grok 4.7 is #32, but their intervals overlap, so treat it as close. It's the usual Grok trade: Grok is a touch better on most writing metrics, by about three points on Visual Cue Quality and two or less elsewhere, while Kimi leads Length Adherence by about nineteen. They cost about the same per script, but Kimi comes back in half the time and ships open weights, so I'd lean Kimi.
Pick Kimi K3 for on-length scripts in half the time, with open weights.
Pick Grok 4.7 for slightly stronger visual cues and voice, if you'll fix the length.
How to read these numbers
Overall vs Elo. Overall is the weighted rubric score. Elo compares each model's five-draft average with every other model's, script by script, and counts gaps inside run-to-run noise as draws, so it rewards winning often and can disagree with overall.
Reading the Elo intervals. Each 95% range comes from resampling every model's recorded run scores on each task and re-ranking. Comparing these separate ranges does not test the Elo gap between two models: far apart is strong evidence, and overlap isn't a tie. The tasks stay fixed, so the ranges say nothing about new tasks (the long version).
Metric by metric: where the gap comes from
Blue is Kimi K3, orange is Grok 4.7, and the solid bar takes the metric. The weight under each name is how much it counts toward the overall. Weighted by how much each metric counts, Length Adherence does the most to put Kimi K3 ahead: it leads there by 18.7 points. If you care about one thing, say voice or length, go straight to that row.
Cost, speed, and consistency
Quality is half the decision. The other half is what each script costs you, how long you wait, and how often you get a bad draft. They cost about the same per script.
| Kimi K3 | Grok 4.7 | |
|---|---|---|
| Overall / 100 | 88.1 | 87.6 |
| Writing Elo | 2208 | 2143 |
| Score spread across drafts (± overall std) | 1.460 | 2.490 |
| Cost per script (USD) | 0.260 | 0.267 |
| Avg time per script (min) | 3.9 | 7.7 |
| Open weights | Yes | No |
Green wins the row, and for spread, cost and time, lower wins. Cost is one script at recorded list prices, uncached and without judging, so your real bill will differ. Spread is how much the overall score moves across a model's drafts, and time is the average time to get one accepted script, retries included.
Want the script-by-script detail? Full scorecards: Kimi K3 · Grok 4.7. The whole scoring pipeline is on the methodology page.
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