GPT-6 Sol vs Composer 2.5
GPT-6 Sol was superseded by GPT-6.1 Sol. The grades below are the last ones measured, so read them as history rather than as this week's board. See the current roster.
GPT-6 Sol leads overall, C- to D. GPT-6 Sol is about 1.3x cheaper per task. By suite, real-world issues is even at C- and GPT-6 Sol takes spec planning (C- to D). Take Composer 2.5 anyway when you want the side that is faster on real-world issues.Measured
Each agent graded on the same private suites, running headless through its own tools. Advantages are oriented so a win is a win, whichever way the metric runs.
Verdict: Composer 2.5 vs GPT-6 Sol
GPT-6 Sol leads overall, C- to D. By suite: real-world issues is even at C- (55% vs 57% capability); GPT-6 Sol takes spec planning, C- to D (60% vs 48% capability); GPT-6 Sol takes vibe coding, C- to F (61% vs 23% capability). GPT-6 Sol used 7% of ChatGPT Plus's weekly limit per pass, $0.017 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.4% of ChatGPT Pro 5x's weekly limit (est, about $0.017 per task). Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, GPT-6 Sol is about 1.3x cheaper ($0.017 vs $0.021). Composer 2.5 is faster on real-world issues: a median task takes 1m 34s against 1m 41s. Both finished every task on it. Reasons to pick Composer 2.5 anyway: it is faster on real-world issues (1m 34s vs 1m 41s median).
Changed since W39: GPT-6 Sol: real-world issues D- to C-, real-world issues usage 4% to 5% of the weekly limit, spec planning C to C-, spec planning usage 1% to 2% of the weekly limit, vibe coding D+ to C-; Composer 2.5: real-world issues D+ to C-.
| Dimension | GPT-6 Sol | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 55% | 57% | +2% (Composer 2.5 leads) |
| Median task time | 1m 41s | 1m 34s | 7s faster (Composer 2.5 leads) |
| Approx. task cost | $0.015 / task | $0.021 / task | $0.006 / task lower (GPT-6 Sol leads) |
GPT-6 Sol: 5.0% of ChatGPT Plus (35.0% / 5h, 5.0% / 1w) per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Composer 2.5: 1.6% of Cursor Pro (1.6% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | GPT-6 Sol | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 60% | 48% | +12% (GPT-6 Sol leads) |
| Median task time | 2m 58s | 1m 8s | 1m 50s faster (Composer 2.5 leads) |
| Approx. task cost | $0.023 / task | $0.022 / task | $0.001 / task lower (Composer 2.5 leads) |
GPT-6 Sol: 2.0% of ChatGPT Plus (10.0% / 5h, 2.0% / 1w) per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Composer 2.5: 0.4% of Cursor Pro (0.4% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | GPT-6 Sol | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 61% | 23% | +39% (GPT-6 Sol leads) |
| Median task time | 2m 44s | 1m 37s | 1m 7s faster (Composer 2.5 leads) |
| Approx. task cost | $0.018 / task | $0.022 / task | $0.003 / task lower (GPT-6 Sol leads) |
GPT-6 Sol: 0.4% of ChatGPT Plus (1.8% / 5h, 0.4% / 1w) per good solve. Its weekly limit holds about 6 of the week's 33.6 5h windows. Composer 2.5: 0.1% of Cursor Pro (0.1% / 1m) per good solve. Each figure is a share of that agent's own plan, so there is no delta to draw.
Grades and deltas are comparable only within a suite version. See methodology.
Frequently asked questions
Which is better for coding, GPT-6 Sol or Composer 2.5?
Both clear tier 1 of 5, but Composer 2.5 scores higher on capability: 57% versus 55% on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-27.
Which is cheaper per task, GPT-6 Sol or Composer 2.5?
GPT-6 Sol used 7% of ChatGPT Plus's weekly limit per pass, $0.017 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.4% of ChatGPT Pro 5x's weekly limit (est, about $0.017 per task). Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, GPT-6 Sol is about 1.3x cheaper ($0.017 vs $0.021).
What do GPT-6 Sol and Composer 2.5 cost a month?
GPT-6 Sol runs on ChatGPT Plus at $20/month (public price as of 2026-07-20). Composer 2.5 runs on Cursor Pro at $20/month (public price as of 2026-07-20).