Model Comparison
GPT-5.6 Terra vs GPT-6.1 Terra
GPT-5.6 Terra (ultra) leads GPT-6.1 Terra (max) by 110 Elo, and their 95% ranges sit 27 Elo apart. Among 84 models, each ranked by its best configuration, GPT-5.6 Terra is #15 and GPT-6.1 Terra is #23. Cost per script: $0.275 for GPT-5.6 Terra (ultra) and $0.079 for GPT-6.1 Terra (max).
Last updated , from board data generated at 20:15 UTC.
Picks and Verdict
PickGPT-5.6 Terra
GPT-5.6 Terra (ultra)
Pick GPT-5.6 Terra (ultra) when quality matters more than the wait, since its range clears every GPT-6.1 Terra row, at $0.275 a script and 8.0 minutes.
PickGPT-6.1 Terra
GPT-6.1 Terra (low)
Pick GPT-6.1 Terra (low) for everyday drafts, since its individual Elo range overlaps GPT-5.6 Terra (medium) and it costs $0.027 a script, less than half as much.
GPT-6.1 Terra is the newer model, but it doesn't write better than GPT-5.6 Terra on this board. GPT-5.6 Terra is the #15 model of 84 and GPT-6.1 Terra the #23 model, each ranked by its best setting. GPT-5.6 Terra (ultra) sits 110 Elo above GPT-6.1 Terra (max), and its 95% range sits clear of every 6.1 row. What 6.1 changed is price and speed. Its five effort levels sit within 25 Elo of each other with overlapping ranges, so I would run it at low, $0.027 a script in about half a minute. GPT-5.6 Terra (medium) overlaps 6.1 at low, 40 Elo ahead, for $0.062 and 1.4 minutes, and ultra costs $0.275 and 8.0 minutes. On 5.6, medium to ultra adds 73 Elo for about 4.4 times the cost, and their individual Elo ranges overlap too. The writing shifted too. 6.1 at low has less slop, 4.6 points better than 5.6 at medium, but a weaker voice, with 5.6 at medium 3.3 points ahead on Tone & Voice Match. Against 6.1 at low, ultra keeps the edge on substance, length and visual cues. I'd use 6.1 at low for everyday drafts and 5.6 at ultra only when a script needs the extra quality and can wait eight minutes.
Disclosure: both models come from the same lab as one of the four judges, GPT-6.1 Sol. The other judges sit outside that lab, so neither is scored by its own lab alone (how the panel works). The judge analysis measures how much each judge favors its own lab.
How to Read the Writing Score, Writing Elo and 95% Ranges
Writing Score and Writing Elo. The Writing Score (0 to 100) is the weighted average of the nine metric scores: seven from the judges, Length Adherence from code and the Slop Score half from each. The Writing Elo is a rating from pairwise comparisons: on each script, each configuration's average across its drafts is compared with every other configuration's, and gaps within the draft-to-draft variation count as draws. Elo rewards winning often, so the two can put configurations in a different order.
Elo ranges. Each 95% range shows how far a configuration's Elo could move if the drafts had come out slightly differently. It comes from resampling every configuration's recorded draft scores on each reference script and ranking again. Comparing two separate ranges does not test the Elo gap between them: ranges far apart are strong evidence for the order, and overlapping ranges do not mean a tie. The reference scripts stay fixed, so the ranges say nothing about new scripts. The methodology page has the full description.
All Thinking Levels of Both Models
Every ranked configuration of GPT-5.6 Terra and GPT-6.1 Terra, scored on the same 10 scripts by the same four judges.
- Each row is one configuration: the model at one thinking level. The dot is its Writing Elo, a rating from pairwise comparisons of the scores on each script, and the bar is its 95% range: how far that Elo could move if the drafts had come out slightly differently.
- Each bar describes one configuration. Overlap alone does not establish a tie or decide their order. Comparing these ranges does not directly test the difference between a pair.
- The table under the chart lists the same configurations in the same order and adds the Writing Score (the 0 to 100 consensus of the judges and code), cost, time and configuration rank (the place among all configurations on the board).
Shaded rows are the configurations chosen for the metric comparison below.
| Configuration | Writing Elo | 95% Range | Writing Score | Cost / Script | Time / Script | Configuration Rank |
|---|---|---|---|---|---|---|
| GPT-5.6 Terra (ultra) | 2033 | 1986 to 2071 | 81.4 | $0.275 | 8.0 min | #27 |
| GPT-5.6 Terra (medium) | 1960 | 1919 to 2003 | 80.7 | $0.062 | 1.4 min | #38 |
| GPT-6.1 Terra (max) | 1923 | 1884 to 1959 | 80.3 | $0.079 | 1.8 min | #43 |
| GPT-6.1 Terra (high) | 1922 | 1881 to 1958 | 80.3 | $0.027 | 0.5 min | #44 |
| GPT-6.1 Terra (low) | 1920 | 1879 to 1961 | 80.2 | $0.027 | 0.5 min | #46 |
| GPT-6.1 Terra (xhigh) | 1906 | 1869 to 1944 | 80.1 | $0.028 | 0.5 min | #48 |
| GPT-6.1 Terra (medium) | 1898 | 1852 to 1942 | 79.9 | $0.027 | 0.5 min | #49 |
Cost is one script at the API list price of the route used, uncached and without judging. Time is the average for one accepted script, retries included.
Computed Findings Across Thinking Levels
Each finding is computed from the configurations above. The 95% ranges describe individual configurations; overlap alone establishes neither a tie nor an order for a pair.
- Best Configurations Head to Head. GPT-5.6 Terra (ultra) leads GPT-6.1 Terra (max) by 110 Elo, and their 95% ranges do not overlap (1986 to 2071 against 1884 to 1959), which is strong evidence for that order.
- Lowest Thinking Levels Head to Head. At their lowest thinking levels, GPT-5.6 Terra (medium) at Elo 1960 and $0.062 per script leads GPT-6.1 Terra (low) at Elo 1920 and $0.027 per script by 40 Elo. Their 95% ranges overlap.
- Same Level Name, Side by Side. At medium, the one level name both models use, GPT-5.6 Terra has the higher Writing Elo: 1960 against 1898. Their 95% ranges overlap there. Level names come from each provider, so the same name does not promise the same reasoning budget.
- Cheapest Configuration Overlapping the Top One. GPT-5.6 Terra (medium), at $0.062 per script, is the cheapest configuration whose 95% range overlaps that of GPT-5.6 Terra (ultra), at $0.275 per script: 1919 to 2003 against 1986 to 2071. GPT-5.6 Terra (ultra) costs about 4.4 times as much per script.
- Cheapest GPT-5.6 Terra Configuration Above GPT-6.1 Terra's Best. The cheapest GPT-5.6 Terra configuration with a higher Writing Elo than GPT-6.1 Terra (max), at Elo 1923 and $0.079 per script, is GPT-5.6 Terra (medium), at Elo 1960 and $0.062 per script. Their 95% ranges overlap. It costs less than the configuration it beats.
- Lowest to Highest Thinking Level. GPT-5.6 Terra moves +73 Elo from medium to ultra, at about 4.4 times the cost per script. GPT-6.1 Terra moves +3 Elo from low to max, at about 2.9 times the cost per script.
Two Chosen Configurations Compared
Pick one configuration of each model to compare their metric scores, consistency across drafts and per-script scores. Each menu starts on the model's best configuration.
Scores by Metric
GPT-5.6 Terra (ultra) scores higher on six of the nine metrics and GPT-6.1 Terra (max) on three. Weighted by each metric's share of the Writing Score, Tone & Voice Match does the most to put GPT-5.6 Terra (ultra) ahead, with a 2.9-point lead on that metric. The weight beside each metric is its share of the Writing Score.
Consistency Across Drafts
| GPT-5.6 Terra (ultra) | GPT-6.1 Terra (max) | |
|---|---|---|
| Score spread across drafts (±) | 1.38 | 1.68 |
| Lowest script score | 79.8 Script 4 | 77.9 Script 10 |
| Highest script score | 83.0 Script 6 | 83.2 Script 9 |
| Range across scripts | 3.2 | 5.3 |
Spread is how much the Writing Score moves between a configuration's drafts, and lower is steadier. Green marks the better number in each row.
Scores by Script
Writing Score on each reference script. Gap is GPT-5.6 Terra (ultra) minus GPT-6.1 Terra (max), and the higher score is in bold.
| Script | GPT-5.6 Terra (ultra) | GPT-6.1 Terra (max) | Gap |
|---|---|---|---|
| Script 1 opinion / warning explainer | 81.1 | 80.2 | +0.9 |
| Script 2 news-analysis / skeptical explainer | 82.1 | 80.7 | +1.4 |
| Script 3 personal roadmap / opinion | 82.5 | 80.4 | +2.1 |
| Script 4 short explainer | 79.8 | 79.6 | +0.2 |
| Script 5 news-analysis / opinion explainer | 82.2 | 80.1 | +2.1 |
| Script 6 founder announcement / personal origin story | 83.0 | 82.2 | +0.8 |
| Script 7 personal technical walkthrough / agentic workflow case study | 80.6 | 79.9 | +0.7 |
| Script 8 product release announcement / personal observation | 80.3 | 79.1 | +1.2 |
| Script 9 career guide / hiring analysis | 81.8 | 83.2 | -1.4 |
| Script 10 engineering process walkthrough / presentation adaptation | 80.6 | 77.9 | +2.7 |
Scorecards and Thinking Pages
Each configuration name in the table above opens its own scorecard.
Compare With Another Model
Pick a second model. A pair with its own written match-up opens that page, and any other pair opens in the comparison tool.
Nearby Match-Ups by Best Writing Elo
Every configuration wrote five drafts for each of the same 10 briefs, from the same prompt. Generation was closed-book, with the prompt as the only source and no web search or other tools. Each judge scores every draft once: Claude Opus 5.5 at medium effort through the Claude Code subscription, GPT-6.1 Sol at medium reasoning through the Codex CLI, GLM 5.3 Flash through OpenRouter, and Jev 1.13, a typed judge from TypeSafe that answers each metric as a multiple-choice question. The channel's finished script is their reference for the voice, and it gets no score on the board itself.
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