🔍 Read the full analysis: How My September 2026 AI Tools Handle Different Jobs on ThorstenMeyerAI.com
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TL;DR
A Sept. 29, 2026, comparison of six AI models argues that task cost and effort settings matter as much as benchmark scores. Its author uses Claude Opus 5.5 for building and GPT-6.1 Sol for detailed review, while reserving other models for narrower jobs. The figures come from Artificial Analysis Intelligence Index v4.3.x and are not proof of performance on every workload.
Thorsten Meyer’s Sept. 29, 2026, model comparison assigns Claude Opus 5.5 to building software and GPT-6.1 Sol to detailed review, arguing that estimated task costs can differ sharply even among models with relatively close benchmark scores. The report matters to teams choosing AI tools because it frames model selection as a trade-off among quality, effort settings and cost, while its results remain benchmark-based rather than verified for each reader’s work.
The comparison covers six models using Artificial Analysis Intelligence Index v4.3.x scores and the source’s cost-per-task estimates. Opus 5.5 leads at 58 index points in its top setting, with an estimated cost of $5.98 per task. GPT-6.1 Sol reaches 51 at xhigh for $0.39; GPT-6 Luna scores 37 at $0.07. The report lists Sonnet 5.5 at 56 and $7.60, Fable 5.1 at 53 and $7.63, and GPT-6 Astra at 53 and $3.26.
Meyer recommends Opus 5.5 at high for routine development, citing a score of 54 and estimated cost of $1.82 per task. He reserves xhigh, at 56 and $3.46, for work such as architecture and migrations. He places GPT-6.1 Sol at high or xhigh for examining specific files and reviewing changes, and says a different model family can provide a useful second review. These are the author’s workflow choices, not independent evaluations of software quality.
The report says effort settings can change estimated costs substantially. For Opus 5.5, moving from medium to max raises the score from 51 to 58 while increasing estimated task cost from $1.34 to $5.98. For Sonnet 5.5, the listed max setting costs $7.60 for a score of 56, compared with $2.74 and a score of 52 at xhigh. Meyer says this makes Sonnet’s high setting a better fit for scoped tasks and documents.
Opus builds. Sol reviews. Jev decides.
One price tape, six models
Score against cost, at every effort setting
The effort dial moves the bill more than the model
Claude Opus 5.5
Claude Sonnet 5.5
GPT-6.1 Sol: near-Astra scores at a fraction of the price
Three published settings
| Setting | Index | Cost per task | Output tokens | First token |
|---|---|---|---|---|
| medium | 48 | $0.21 | 15M | 5.3 s |
| high | 50 | $0.32 | 25M | 57 s |
| xhigh | 51 | $0.39 | 36M | 69 s |
Same score band, very different bill
My stack: who builds, who reviews
Cheaper tokens are not cheaper work
Read the numbers with four warnings
Part 2: Jev, the model that decides instead of writing
One call in, typed answers out
Three question types
Confidence is the superpower
Three uses running in my publishing operation
The fit test, then the shadow test
- Replay 300 to 500 past decisions
- Compare overall and per confidence band
- Read 20 disagreements, decide who was right
- High band at 95% or better?
- Own flag, off by default
- Canary on 5 to 10 units
- Roll out in the confident band only
24 use cases, sorted by how well they fit
Proven in production
- 1Relevance gate
- 2Language check
- 3Classifier fallback
Publishing and content
- 4Thin-source detector
- 5Same-event dedupe
- 6Product fits roundup
- 7Disclosure present
- 8Headline quality
- 9Comment moderation
Commerce and support
- 10Support-ticket routing
- 11Return-reason coding
- 12Review to feature complaints
- 13Catalogue taxonomy
- 14Order-fraud pre-triage
Software and AI systems
- 15LLM guardrail
- 16RAG passage filter
- 17Citation check
- 18Tool and intent routing
- 19Log-line triage
- 20PR risk triage
Business ops and home
- 21Inbox triage
- 22Expense categorisation
- 23Lead qualification
- 24Smart-home intent
Limits, cost and one hard rule
Cost Shapes the Model Assignment
The report’s central implication is that the highest score may not be the most economical choice for every task. Meyer’s figures put GPT-6.1 Sol’s xhigh estimate at $0.39 per task, compared with $3.26 for Astra and $7.63 for Fable 5.1, while their top scores sit within a few points of one another. If those estimates translate to a team’s own workload, using a lower-cost model for repeated reviews or classification could affect operating costs.
But the comparison itself does not establish that the models produce equivalent results on a particular company’s code, documents or routing decisions. Meyer advises readers to shadow-test models against their own quality bar before switching. He also cautions that savings in model charges may be outweighed by added human review time; his example is illustrative, not a measured result.
A New Model Joins the Comparison
The source dates the releases across September: Fable 5.1 on Sept. 1, Astra on Sept. 3, Opus 5.5 on Sept. 22, Luna on Sept. 22 and Sonnet 5.5 on Sept. 28. GPT-6.1 Sol was released Sept. 29, the day the comparison was published. The author says it has the same listed token prices as GPT-6 Sol: $2 per million input tokens and $10 per million output tokens.
The Artificial Analysis Intelligence Index is described in the source as a measure of general capability, rather than a verdict on a specific workload. The report also lists token output and time-to-first-token figures for Sol: at high, 25 million output tokens on the index and 57 seconds to first token; at xhigh, 36 million and 69 seconds. The author says these longer waits make those settings unsuitable for interactive use.
“The practical reading: Sol is not the model I ask to build. It is the model I can afford to run on everything.”
— Thorsten Meyer
Workload Results Remain Open
The source does not provide independent, task-specific comparisons showing how the models perform on readers’ workloads. Its per-task costs are estimates tied to the stated index runs, and the material supplied does not fully define the task-cost calculation or its applicability to other usage patterns. Meyer also says one index point is within the noise, and Artificial Analysis had not published low or max settings for GPT-6.1 Sol at the time of writing. The report does not establish whether the listed costs or benchmark standings will hold as models and pricing change.
Test Before Changing Workflows
Meyer’s proposed next step is for teams to shadow-test candidate models on their own tasks before changing assignments. That would let them compare output quality and review time against actual costs. The source gives no date for new benchmark settings or a follow-up comparison, so the timing of further updates is unclear.
Key Questions
Which model does Meyer use for building?
He says he uses Claude Opus 5.5 at high for routine development, and xhigh for harder work such as architecture and migrations.
Why does he use GPT-6.1 Sol for review?
Meyer cites its estimated cost of $0.32 at high and $0.39 at xhigh and uses it to inspect files and diffs. He says a different model family can act as a second reviewer; this is his practice, not a guarantee of independent or correct review.
Does the benchmark show which model is best for every task?
No. The source describes the Artificial Analysis Intelligence Index as a general capability measure and recommends testing models on the work they would actually handle.
What remains unknown about the cost figures?
The supplied report does not fully explain how its per-task estimates translate to other workloads or usage patterns. Teams would need to compare their own quality, usage and human review costs.
Source: ThorstenMeyerAI.com
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