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Model comparison

GPT-5.5 vs GPT-5.6 Sol

Data verified

Head-to-head evidence from 39 shared benchmark results across 7 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

GPT-5.5
OpenAI
73.51/100
Margin
8.4pts
winning →
81.96/100
0 category wins5 category wins

Public leaderboard positions: GPT-5.5 #9 (Estimated); GPT-5.6 Sol #3 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. GPT-5.5 and GPT-5.6 Sol share 39 comparable benchmark results. 5 of 8 categories are comparable. 18 results are unique to GPT-5.5; 7 to GPT-5.6 Sol.

Updated July 23, 2026
Shared results
39
GPT-5.5 only
18
GPT-5.6 Sol only
7
Comparable categories
5 / 8

Pick GPT-5.6 Sol if you want the stronger benchmark profile. GPT-5.5 only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.

Confidence note. This is a partial-evidence comparison with 39 shared benchmark results across 7 evidence categories; 5 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

GPT-5.6 Sol is clearly ahead on the BenchAlign aggregate, 81.96 to 73.51. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.6 Sol's sharpest advantage is in mathematics, where it averages 87.5 against 47.6. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 35.400% to 83.000%.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for GPT-5.5 and GPT-5.6 Sol
CategoryGPT-5.5ΔGPT-5.6 Sol
MathGPT-5.547.6Margin→ 39.9GPT-5.6 Sol87.5
KnowledgeGPT-5.557.8Margin→ 36.8GPT-5.6 Sol94.6
MultimodalGPT-5.570.4Margin→ 12.6GPT-5.6 Sol83.0
AgenticGPT-5.581.6Margin→ 10.4GPT-5.6 Sol92.0
CodingGPT-5.558.6Margin→ 6.0GPT-5.6 Sol64.6
ReasoningGPT-5.585.0MarginNo overlapGPT-5.6 SolNot measured

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · GPT-5.5B · GPT-5.6 Sol

  1. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 35.400%B 83.000%
    Winner: GPT-5.6 SolΔ 47.6
    FrontierMath v2 (Tier 4): GPT-5.5 scored 35.400%; GPT-5.6 Sol scored 83.000%. GPT-5.6 Sol wins this benchmark.

  2. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 51.700%B 89.000%
    Winner: GPT-5.6 SolΔ 37.3
    FrontierMath v2 (Tiers 1-3): GPT-5.5 scored 51.700%; GPT-5.6 Sol scored 89.000%. GPT-5.6 Sol wins this benchmark.

  3. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 82%B 91.9%
    Winner: GPT-5.6 SolΔ 9.9
    Terminal-Bench 2.0: GPT-5.5 scored 82%; GPT-5.6 Sol scored 91.9%. GPT-5.6 Sol wins this benchmark.

  4. BrowseComp

    Agentic
    Source ↗
    A 84.4%B 92.2%
    Winner: GPT-5.6 SolΔ 7.8
    BrowseComp: GPT-5.5 scored 84.4%; GPT-5.6 Sol scored 92.2%. GPT-5.6 Sol wins this benchmark.

  5. SWE-bench Pro

    Coding
    Source ↗
    A 58.6%B 64.6%
    Winner: GPT-5.6 SolΔ 6
    SWE-bench Pro: GPT-5.5 scored 58.6%; GPT-5.6 Sol scored 64.6%. GPT-5.6 Sol wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricGPT-5.5GPT-5.6 SolComparison
Input / output priceUSD per 1M tokensGPT-5.5$5 input / $30 outputGPT-5.6 Sol$5 input / $30 outputListed prices are equal.
Generation speedtokens per secondGPT-5.5Not availableGPT-5.6 SolNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenGPT-5.5Not availableGPT-5.6 SolNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensGPT-5.51MGPT-5.6 Sol1MListed context windows are equal.

Benchmark Deep Dive

AgenticGPT-5.6 Sol wins
BenchmarkGPT-5.5GPT-5.6 SolResult
Terminal-Bench 2.0Source 82%91.9%GPT-5.6 Sol leads
CyberGymSource 81.8%84.5%GPT-5.6 Sol leads
BrowseCompSource 84.4%92.2%GPT-5.6 Sol leads
OSWorld-VerifiedSource 78.7%—Not comparable
MCP AtlasSource 75.3%—Not comparable
ToolathlonSource 55.6%58%GPT-5.6 Sol leads
τ²-bench resultsSource 93.9%85.1%GPT-5.5 leads
AA Agentic IndexSource 44.9%54.0%GPT-5.6 Sol leads
APEX-Agents-AASource 37.7%—Not comparable
GDPval-AASource 49.5%61.8%GPT-5.6 Sol leads
GDPval-AASource 14901736GPT-5.6 Sol leads
Gert LabsSource 72.93%—Not comparable
ResearchClawBenchSource 17.0%—Not comparable
OSWorld 2.0Source 13.0%62.6%GPT-5.6 Sol leads
JobBenchSource 42.7%—Not comparable
ExploitGymSource 13.4%33.7%GPT-5.6 Sol leads
AA BriefcaseSource 11541501GPT-5.6 Sol leads
AA AutomationBenchSource 42.1%51.2%GPT-5.6 Sol leads
AA EnterpriseOps-GymSource 46.6%—Not comparable
AA Harvey LABSource 86.3%87.2%GPT-5.6 Sol leads
AA ITBenchSource 45.8%56.2%GPT-5.6 Sol leads
AA Tau3 BankingSource 31.3%33.0%GPT-5.6 Sol leads
terminalBenchHardSource 60.6%65.9%GPT-5.6 Sol leads
aaTerminalBench21Source 84.3%88%GPT-5.6 Sol leads
CodingGPT-5.6 Sol wins
BenchmarkGPT-5.5GPT-5.6 SolResult
SWE-bench ProSource 58.6%64.6%GPT-5.6 Sol leads
Terminal-Bench 2.0Source 82.0%91.9%GPT-5.6 Sol leads
Vibe Code BenchSource 69.85%—Not comparable
React Native EvalsSource 84.7%—Not comparable
cursorBench31Source 59.2%—Not comparable
cursorBench32Source 58.4%67.2%GPT-5.6 Sol leads
AA Coding IndexSource 74.9%77.4%GPT-5.6 Sol leads
AA-SciCodeSource 56.1%56.1%Tie
FrontierCode 1.1 MainSource 43.0%—Not comparable
deepSweSource —72.7%Not comparable
FrontierCode 1.1 ExtendedSource —60.6%Not comparable
VulcanBench v3Source —87.0%Not comparable
Reasoning
BenchmarkGPT-5.5GPT-5.6 SolResult
MRCR v2 64K-128KSource 83.1%—Not comparable
MRCR v2 128K-256KSource 87.5%—Not comparable
ARC-AGI-2Source 85%—Not comparable
AA-LCRSource 74.3%73.7%GPT-5.5 leads
CritPtSource 27.1%32.3%GPT-5.6 Sol leads
ARC-AGI-3Source —7.8%Not comparable
GeneBench-ProSource —28.7%Not comparable
KnowledgeGPT-5.6 Sol wins
BenchmarkGPT-5.5GPT-5.6 SolResult
GPQASource 93.6%94.6%GPT-5.6 Sol leads
GPQA-DSource 93.6%94.6%GPT-5.6 Sol leads
HLESource 52.2%—Not comparable
HLE w/o toolsSource 41.4%—Not comparable
Artificial Analysis Intelligence IndexSource 54.8%58.9%GPT-5.6 Sol leads
AA-GPQA DiamondSource 93.5%94.1%GPT-5.6 Sol leads
AA-HLESource 44.3%47.2%GPT-5.6 Sol leads
AA-Omniscience IndexSource 20.1%21.7%GPT-5.6 Sol leads
AA-Omniscience AccuracySource 56.9%58.5%GPT-5.6 Sol leads
AA-Omniscience Hallucination RateSource 85.5%88.8%GPT-5.5 leads
HealthBench ProfessionalSource —60.5%Not comparable
HealthBench HardSource —33.1%Not comparable
MathGPT-5.6 Sol wins
BenchmarkGPT-5.5GPT-5.6 SolResult
FrontierMath (legacy)Source 51.7%89%GPT-5.6 Sol leads
FrontierMath v2 (Tiers 1-3)Source 51.700%89.000%GPT-5.6 Sol leads
FrontierMath v2 (Tier 4)Source 35.400%83.000%GPT-5.6 Sol leads
MultimodalGPT-5.6 Sol wins
BenchmarkGPT-5.5GPT-5.6 SolResult
MMMU-ProSource 81.2%83%GPT-5.6 Sol leads
MMMU-Pro w/ PythonSource 83.2%84.6%GPT-5.6 Sol leads
OfficeQA ProSource 54.1%—Not comparable
AA-MMMU-ProSource 79.9%83.4%GPT-5.6 Sol leads
Design Arena WebsiteSource 1282—Not comparable
Inst. Following
BenchmarkGPT-5.5GPT-5.6 SolResult
AA-IFBenchSource 75.9%72.7%GPT-5.5 leads
Frequently Asked Questions (6)

Which is better, GPT-5.5 or GPT-5.6 Sol?

GPT-5.6 Sol is ahead on BenchLM's BenchAlign leaderboard, 81.96 to 73.51. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 35.400% and 83.000%.

Which is better for knowledge tasks, GPT-5.5 or GPT-5.6 Sol?

GPT-5.6 Sol has the edge for knowledge tasks in this comparison, averaging 94.6 versus 57.8. Inside this category, Artificial Analysis Intelligence Index is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.5 or GPT-5.6 Sol?

GPT-5.6 Sol has the edge for coding in this comparison, averaging 64.6 versus 58.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.5 or GPT-5.6 Sol?

GPT-5.6 Sol has the edge for math in this comparison, averaging 87.5 versus 47.6. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.5 or GPT-5.6 Sol?

GPT-5.6 Sol has the edge for agentic tasks in this comparison, averaging 92 versus 81.6. Inside this category, AA Briefcase is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-5.5 or GPT-5.6 Sol?

GPT-5.6 Sol has the edge for multimodal and grounded tasks in this comparison, averaging 83 versus 70.4. Inside this category, AA-MMMU-Pro is the benchmark that creates the most daylight between them.

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