Grok 4.5 vs DeepSeek V4 Flash 0731
Should you write with Grok 4.5 or DeepSeek V4 Flash 0731? 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 three judges from three model families scored every draft blind, with my finished script as the reference. DeepSeek V4 Flash 0731 leads overall, 84.4 to 81.9.
The verdict
The cheaper model scores better here, and it costs almost nothing. DeepSeek V4 Flash 0731 ranks #59 against #76 for Grok 4.5 and wins seven of the nine metrics. Two stand out: the hook, almost five points up, and Length Adherence, about thirteen. Grok 4.5 holds a slightly better Slop Score and basically ties on substance. Then there's price: $0.005 per script against $0.063, with open weights on the DeepSeek side. Grok's one practical edge is speed, since it comes back in under a minute.
Pick Grok 4.5 when turnaround speed matters more than script quality.
Pick DeepSeek V4 Flash 0731 as the default: better scores, open weights, and about half a cent per script.
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. My own scripts score 90.9 on the same rubric, not a literal 100. Right now 2 of 167 ranked configurations reach it. A model above that line writes at that level on this rubric. That's not the same as beating my script line for line.
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 Grok 4.5, orange is DeepSeek V4 Flash 0731, 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 DeepSeek V4 Flash 0731 ahead: it leads there by 12.9 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. DeepSeek V4 Flash 0731 is ahead and it's also the cheaper one: Grok 4.5 costs about 13x as much per script.
| Grok 4.5 | DeepSeek V4 Flash 0731 | |
|---|---|---|
| Overall / 100 | 81.9 | 84.4 |
| Writing Elo | 1618 | 1866 |
| Score spread across drafts (± overall std) | 2.950 | 3.360 |
| Cost per script (USD) | 0.063 | 0.005 |
| Avg time per script (min) | 0.9 | 3.1 |
| Open weights | No | Yes |
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: Grok 4.5 · DeepSeek V4 Flash 0731. The whole scoring pipeline is on the methodology page.
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