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Model comparison

Claude Mythos 5 vs Gemini 3.5 Flash

Data verified

Head-to-head evidence from 7 shared benchmark results across 4 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

83.93/100
Margin
19.2pts
← winning
64.75/100
5 category wins0 category wins

Public leaderboard positions: Claude Mythos 5 #1 (Supported); Gemini 3.5 Flash #33 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Mythos 5 and Gemini 3.5 Flash share 7 comparable benchmark results. 5 of 8 categories are comparable. 8 results are unique to Claude Mythos 5; 39 to Gemini 3.5 Flash.

Updated July 23, 2026
Shared results
7
Claude Mythos 5 only
8
Gemini 3.5 Flash only
39
Comparable categories
5 / 8

Pick Claude Mythos 5 if you want the stronger benchmark profile. Gemini 3.5 Flash only becomes the better choice if you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 7 shared benchmark results across 4 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

Claude Mythos 5 is clearly ahead on the BenchAlign aggregate, 83.93 to 64.75. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Mythos 5's sharpest advantage is in mathematics, where it averages 97.6 against 32.9. The single biggest benchmark swing on the page is SWE-bench Pro, 80.3% to 55.1%.

Claude Mythos 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $1.50 input / $9.00 output per 1M tokens for Gemini 3.5 Flash. That is roughly 5.6x on output cost alone. Claude Mythos 5 gives you the larger context window at 1M+, compared with 1M for Gemini 3.5 Flash.

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 Claude Mythos 5 and Gemini 3.5 Flash
CategoryClaude Mythos 5ΔGemini 3.5 Flash
MathClaude Mythos 597.6Margin← 64.7Gemini 3.5 Flash32.9
CodingClaude Mythos 589.7Margin← 35.8Gemini 3.5 Flash53.9
KnowledgeClaude Mythos 568.5Margin← 21.3Gemini 3.5 Flash47.2
AgenticClaude Mythos 587.0Margin← 9.8Gemini 3.5 Flash77.2
MultimodalClaude Mythos 593.5Margin← 9.7Gemini 3.5 Flash83.8
ReasoningClaude Mythos 5Not measuredMarginNo overlapGemini 3.5 Flash74.7
Inst. FollowingClaude Mythos 5Not measuredMarginNo overlapGemini 3.5 Flash76.3

Decisive benchmark drivers

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

More
A · Claude Mythos 5B · Gemini 3.5 Flash

  1. SWE-bench Pro

    Coding
    Source ↗
    A 80.3%B 55.1%
    Winner: Claude Mythos 5Δ 25.2
    SWE-bench Pro: Claude Mythos 5 scored 80.3%; Gemini 3.5 Flash scored 55.1%. Claude Mythos 5 wins this benchmark.

  2. HLE

    Knowledge
    Source ↗
    A 64.5%B 40.2%
    Winner: Claude Mythos 5Δ 24.3
    HLE: Claude Mythos 5 scored 64.5%; Gemini 3.5 Flash scored 40.2%. Claude Mythos 5 wins this benchmark.

  3. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 88%B 76.2%
    Winner: Claude Mythos 5Δ 11.8
    Terminal-Bench 2.0: Claude Mythos 5 scored 88%; Gemini 3.5 Flash scored 76.2%. Claude Mythos 5 wins this benchmark.

  4. CharXiv

    Multimodal
    Source ↗
    A 93.5%B 84.2%
    Winner: Claude Mythos 5Δ 9.3
    CharXiv: Claude Mythos 5 scored 93.5%; Gemini 3.5 Flash scored 84.2%. Claude Mythos 5 wins this benchmark.

  5. OSWorld-Verified

    Agentic
    Source ↗
    A 85%B 78.4%
    Winner: Claude Mythos 5Δ 6.6
    OSWorld-Verified: Claude Mythos 5 scored 85%; Gemini 3.5 Flash scored 78.4%. Claude Mythos 5 wins this benchmark.

Operational comparison

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

MetricClaude Mythos 5Gemini 3.5 FlashComparison
Input / output priceUSD per 1M tokensClaude Mythos 5$10 input / $50 outputGemini 3.5 Flash$1.5 input / $9 outputGemini 3.5 Flash has the lower combined listed price.
Generation speedtokens per secondClaude Mythos 5Not availableGemini 3.5 Flash284.2 tok/sA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Mythos 5Not availableGemini 3.5 Flash18.55 sA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Mythos 51M+Gemini 3.5 Flash1MClaude Mythos 5 lists the larger context window.

Benchmark Deep Dive

AgenticClaude Mythos 5 wins
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
Terminal-Bench 2.0Source 88%76.2%Claude Mythos 5 leads
OSWorld-VerifiedSource 85%78.4%Claude Mythos 5 leads
BrowseCompSource 88%—Not comparable
ExploitGymSource 17.5%—Not comparable
MCP AtlasSource —83.6%Not comparable
ToolathlonSource —56.5%Not comparable
Finance Agent v2Source —57.9%Not comparable
GDPval-AASource —1349Not comparable
τ²-bench resultsSource —95.3%Not comparable
GDPval-AASource —42.4%Not comparable
AA Agentic IndexSource —37.5%Not comparable
APEX-Agents-AASource —47.1%Not comparable
Gert LabsSource —61.85%Not comparable
ResearchClawBenchSource —18.0%Not comparable
AA AutomationBenchSource —42.6%Not comparable
AA EnterpriseOps-GymSource —50.1%Not comparable
terminalBenchHardSource —40.9%Not comparable
CodingClaude Mythos 5 wins
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
SWE-bench VerifiedSource 95.5%—Not comparable
SWE-bench ProSource 80.3%55.1%Claude Mythos 5 leads
Terminal-Bench 2.0Source 88.0%76.2%Claude Mythos 5 leads
SciCodeSource —53.1%Not comparable
Vibe Code BenchSource —48.68%Not comparable
cursorBench31Source —49.8%Not comparable
cursorBench32Source —48.8%Not comparable
AA Coding IndexSource —70.1%Not comparable
AA-SciCodeSource —53.1%Not comparable
Reasoning
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
MRCRv2Source —77.3%Not comparable
MRCR 1MSource —26.6%Not comparable
ARC-AGI-2Source —72.1%Not comparable
AA-LCRSource —69.3%Not comparable
CritPtSource —13.1%Not comparable
KnowledgeClaude Mythos 5 wins
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
GPQASource 94.1%92.2%Claude Mythos 5 leads
HLESource 64.5%40.2%Claude Mythos 5 leads
HLE w/o toolsSource 59%—Not comparable
Artificial Analysis Intelligence IndexSource —50.2%Not comparable
GPQA-DSource —92.7%Not comparable
AA-Omniscience AccuracySource —51.9%Not comparable
AA-Omniscience Hallucination RateSource —60.7%Not comparable
AA-GPQA DiamondSource —92.2%Not comparable
AA-HLESource —41.0%Not comparable
AA-Omniscience IndexSource —22.7%Not comparable
MathClaude Mythos 5 wins
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
USAMO 2026Source 97.6%—Not comparable
FrontierMath v2 (Tiers 1-3)Source —38.966%Not comparable
FrontierMath v2 (Tier 4)Source —14.583%Not comparable
Multilingual
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
SWE MultilingualSource 92.2%—Not comparable
MultimodalClaude Mythos 5 wins
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
SWE-bench MultimodalSource 54.9%—Not comparable
CharXivSource 93.5%84.2%Claude Mythos 5 leads
CharXiv w/o toolsSource 88.9%—Not comparable
MMMU-ProSource —83.6%Not comparable
Blueprint-Bench 2Source —33.6%Not comparable
AA-MMMU-ProSource —84.3%Not comparable
Design Arena WebsiteSource —1285Not comparable
Inst. Following
BenchmarkClaude Mythos 5Gemini 3.5 FlashResult
IFBenchSource —76.3%Not comparable
AA-IFBenchSource —76.3%Not comparable
Frequently Asked Questions (6)

Which is better, Claude Mythos 5 or Gemini 3.5 Flash?

Claude Mythos 5 is ahead on BenchLM's BenchAlign leaderboard, 83.93 to 64.75. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 80.3% and 55.1%.

Which is better for knowledge tasks, Claude Mythos 5 or Gemini 3.5 Flash?

Claude Mythos 5 has the edge for knowledge tasks in this comparison, averaging 68.5 versus 47.2. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, Claude Mythos 5 or Gemini 3.5 Flash?

Claude Mythos 5 has the edge for coding in this comparison, averaging 89.7 versus 53.9. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, Claude Mythos 5 or Gemini 3.5 Flash?

Claude Mythos 5 has the edge for math in this comparison, averaging 97.6 versus 32.9. Gemini 3.5 Flash stays close enough that the answer can still flip depending on your workload.

Which is better for agentic tasks, Claude Mythos 5 or Gemini 3.5 Flash?

Claude Mythos 5 has the edge for agentic tasks in this comparison, averaging 87 versus 77.2. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, Claude Mythos 5 or Gemini 3.5 Flash?

Claude Mythos 5 has the edge for multimodal and grounded tasks in this comparison, averaging 93.5 versus 83.8. Inside this category, CharXiv is the benchmark that creates the most daylight between them.

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