GPT-5.6 Sol vs GPT-6.1 Sol
Reading a 26.2K-token pull request costs $0.1048 on GPT-5.6 Sol, 2.0× the $0.0524 it costs on GPT-6.1 Sol. Both are GPT Sol models, so the difference is one version of the same line against another. The benchmark cannot separate their recall: GPT-5.6 Sol minus GPT-6.1 Sol is −17 pts (95% interval −29 pts to −6 pts).
Side by side
| Figure | GPT-5.6 Sol | GPT-6.1 Sol |
|---|---|---|
| Price tier | Frontier | Mid-range |
| Bugs caughtshare of known bugs | 72% | 89% (better) |
| False alarmsper clean PR | 1.2 | 0.9 (better) |
| Cost per reviewmeasured | $0.1127 | $0.0401 (better) |
| Cost per bug caught | $0.1732 | $0.0514 (better) |
| Exact linecatches on the expected lines | 92% | 95% (better) |
| Review timemean | 50s | 28s (better) |
| Typical review calllist price | $0.1532 | $0.0766 (better) |
| Input / 1M tokens | $4.00 | $2.00 (better) |
| Output / 1M tokens | $20.00 | $10.00 (better) |
| Context window | 1.1M | 1.1M |
Head to head
The known bugs both were scored on, by who caught each in at least one run.
By language
| Model | All | TypeScript6 bugs | Go4 bugs | Java4 bugs | Rust4 bugs | C#3 bugs | JavaScript3 bugs | Kotlin3 bugs | PHP3 bugs | Python3 bugs | Ruby3 bugs | Swift3 bugs | C++2 bugs | C1 bug |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GPT-5.6 Sol | 72% | 67% | 50% | 69% | 75% | 56% | 100% | 67% | 100% | 100% | 67% | 100% | 50% | 0% |
| GPT-6.1 Sol | 89% | 83% | 75% | 70% | 100% | 89% | 100% | 100% | 100% | 100% | 100% | 100% | 50% | 100% |
Of the 42 known bugs both were scored on, both caught 31 and neither caught 3. GPT-5.6 Sol caught one bug that GPT-6.1 Sol missed: 1 in Java. GPT-6.1 Sol caught 7 bugs that GPT-5.6 Sol missed: 1 in C, 1 in C#, 1 in Go, 1 in Kotlin, 1 in Ruby, 1 in Rust and 1 in TypeScript, most of them logic bugs.
On pull requests with no known bug, GPT-5.6 Sol raised 1.2 false alarms per review and GPT-6.1 Sol 0.9. A measured review cost $0.1127 on GPT-5.6 Sol, 2.8× the cost of $0.0401 on GPT-6.1 Sol.
| Pull request | Language · kind | GPT-5.6 Sol | GPT-6.1 Sol |
|---|---|---|---|
| jhy/jsoupStore cached child els in Attributes, not field | Java · Concurrency | 1/6 | 0/2 |
| c-ares/c-aresEvent Thread could stall when not notified of new queries on existing connections that are in a bad state | C · Resource handling | 0/1 | 1/1 |
| dotnet/orleansfix(serialization): cap codec allocations | C# · Logic | 0/1 | 1/1 |
| kotest/kotestFix DataClassEq comparator | Kotlin · Logic | 0/1 | 1/1 |
| nushell/nushellreorganize nushell configuration | Rust · Error handling | 0/1 | 1/1 |
| rails/railsReimplement Action Cable redis adapter with redis-client | Ruby · Logic | 0/1 | 1/1 |
| traefik/traefikAdd the option to define custom cipher suites for backend serversTransport | Go · API misuse | 0/1 | 1/1 |
| withastro/astroPort Go's csrf protection | TypeScript · Logic | 0/1 | 1/1 |
Defects caught over all runs: a PR reviewed three times with one known bug shows 3/3 when it was caught every time.
Every bug each was scored on: GPT-5.6 Sol and GPT-6.1 Sol.