Gemini 3.8 Flash vs GPT-5.6 Sol
GPT-5.6 Sol was superseded by GPT-6.1 Sol.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.
Both grade C- overall. GPT-5.6 Sol is about 1.6x cheaper per task. By suite, real-world issues is even at C- and GPT-5.6 Sol takes spec planning (C+ to D+). Both agents run the same private suite cut headless through their own tools, each on its own subscription.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: GPT-5.6 Sol vs Gemini 3.8 Flash
Both grade C- overall. By suite: real-world issues is even at C- (60% vs 60% capability); GPT-5.6 Sol takes spec planning, C+ to D+ (68% vs 50% capability); Gemini 3.8 Flash takes vibe coding, C- to D+ (56% vs 51% capability). Gemini 3.8 Flash used 23.7% of Google AI Pro's weekly limit per pass, $0.057 per task at the listed price. GPT-5.6 Sol used 3% of ChatGPT Pro 5x's weekly limit per pass, $0.036 per task at the listed price. Per task, GPT-5.6 Sol is about 1.6x cheaper ($0.036 vs $0.057). GPT-5.6 Sol is faster on real-world issues: a median task takes 3m 13s against 5m 21s. Both finished every task on it.
Changed since the previous graded week: Gemini 3.8 Flash: real-world issues F to C-, real-world issues usage 18.0% to 21.9% of the weekly limit, spec planning usage 2.0% to 1.8% of the weekly limit, vibe coding D+ to C-, vibe coding usage 1.2% to 1.1% of the weekly limit; GPT-5.6 Sol: vibe coding C- to D+.
| Dimension | Gemini 3.8 Flash | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 60% | 60% | Even |
| Median task time | 5m 21s | 3m 13s | 2m 8s faster (GPT-5.6 Sol leads) |
| Approx. task cost | $0.067 / task | $0.031 / task | $0.036 / task lower (GPT-5.6 Sol leads) |
Gemini 3.8 Flash: 21.9% of Google AI Pro (131.3% / 5h, 21.9% / 1w) per run. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-5.6 Sol: 2.0% of ChatGPT Pro 5x (2.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Gemini 3.8 Flash | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 50% | 68% | +18% (GPT-5.6 Sol leads) |
| Median task time | 3m 0s | 6m 0s | 2m 59s faster (Gemini 3.8 Flash leads) |
| Approx. task cost | $0.021 / task | $0.057 / task | $0.036 / task lower (Gemini 3.8 Flash leads) |
Gemini 3.8 Flash: 1.8% of Google AI Pro (11.0% / 5h, 1.8% / 1w) per run. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-5.6 Sol: 1.0% of ChatGPT Pro 5x (1.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Gemini 3.8 Flash | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 56% | 51% | +5% (Gemini 3.8 Flash leads) |
| Median task time | 7m 51s | 3m 56s | 3m 55s faster (GPT-5.6 Sol leads) |
| Approx. task cost | $0.048 / task | $0.092 / task | $0.044 / task lower (Gemini 3.8 Flash leads) |
Gemini 3.8 Flash: 1.1% of Google AI Pro (6.3% / 5h, 1.1% / 1w) per good solve. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-5.6 Sol: 0.4% of ChatGPT Pro 5x (0.4% / 1w) 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, Gemini 3.8 Flash or GPT-5.6 Sol?
They are even on our ladder: both clear tier 4 of 5 at 60% capability on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-27.
Which is cheaper per task, Gemini 3.8 Flash or GPT-5.6 Sol?
Gemini 3.8 Flash used 23.7% of Google AI Pro's weekly limit per pass, $0.057 per task at the listed price. GPT-5.6 Sol used 3% of ChatGPT Pro 5x's weekly limit per pass, $0.036 per task at the listed price. Per task, GPT-5.6 Sol is about 1.6x cheaper ($0.036 vs $0.057).