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Model comparison

Claude Opus 4.5 vs DeepSeek V4 Flash Base

Data verified

Head-to-head evidence from 5 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

64.22/100
No comparison
N/A
2 category wins0 category wins

Public leaderboard positions: Claude Opus 4.5 #34 (Supported); DeepSeek V4 Flash Base unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Opus 4.5 and DeepSeek V4 Flash Base share 5 comparable benchmark results. 2 of 8 categories are comparable. 54 results are unique to Claude Opus 4.5; 19 to DeepSeek V4 Flash Base.

Updated July 23, 2026
Shared results
5
Claude Opus 4.5 only
54
DeepSeek V4 Flash Base only
19
Comparable categories
2 / 8

Treat this as a split decision. Claude Opus 4.5 makes more sense if reasoning is the priority; DeepSeek V4 Flash Base is the better fit if you need the larger 1M context window.

Confidence note. This is a partial-evidence comparison with 5 shared benchmark results across 2 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Claude Opus 4.5 and DeepSeek V4 Flash Base finish on the same BenchAlign overall score, so this is less about a single winner and more about where the edge shows up. The BenchAlign headline says tie; the benchmark table is where the real choice happens.

DeepSeek V4 Flash Base gives you the larger context window at 1M, compared with 200K for Claude Opus 4.5.

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 Opus 4.5 and DeepSeek V4 Flash Base
CategoryClaude Opus 4.5ΔDeepSeek V4 Flash Base
ReasoningClaude Opus 4.564.4Margin← 19.7DeepSeek V4 Flash Base44.7
KnowledgeClaude Opus 4.558.1Margin← 1.7DeepSeek V4 Flash Base56.4
AgenticClaude Opus 4.562.6MarginNo overlapDeepSeek V4 Flash BaseNot measured
CodingClaude Opus 4.571.7MarginNo overlapDeepSeek V4 Flash BaseNot measured
MathClaude Opus 4.557.5MarginNo overlapDeepSeek V4 Flash BaseNot measured
MultilingualClaude Opus 4.585.7MarginNo overlapDeepSeek V4 Flash BaseNot measured
MultimodalClaude Opus 4.569.9MarginNo overlapDeepSeek V4 Flash BaseNot measured
Inst. FollowingClaude Opus 4.569.5MarginNo overlapDeepSeek V4 Flash BaseNot measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.5B · DeepSeek V4 Flash Base

  1. SuperGPQA

    Knowledge
    Source ↗
    A 70.6%B 46.5%
    Winner: Claude Opus 4.5Δ 24.1
    SuperGPQA: Claude Opus 4.5 scored 70.6%; DeepSeek V4 Flash Base scored 46.5%. Claude Opus 4.5 wins this benchmark.

  2. MMLU-Pro

    Knowledge
    Source ↗
    A 89.5%B 68.3%
    Winner: Claude Opus 4.5Δ 21.2
    MMLU-Pro: Claude Opus 4.5 scored 89.5%; DeepSeek V4 Flash Base scored 68.3%. Claude Opus 4.5 wins this benchmark.

  3. LongBench v2

    Reasoning
    Source ↗
    A 64.4%B 44.7%
    Winner: Claude Opus 4.5Δ 19.7
    LongBench v2: Claude Opus 4.5 scored 64.4%; DeepSeek V4 Flash Base scored 44.7%. Claude Opus 4.5 wins this benchmark.

Operational comparison

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

MetricClaude Opus 4.5DeepSeek V4 Flash BaseComparison
Input / output priceUSD per 1M tokensClaude Opus 4.5$5 input / $25 outputDeepSeek V4 Flash BaseNot availableA complete price comparison is not available.
Generation speedtokens per secondClaude Opus 4.546 tok/sDeepSeek V4 Flash BaseNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.51.01 sDeepSeek V4 Flash BaseNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.5200KDeepSeek V4 Flash Base1MDeepSeek V4 Flash Base lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
Terminal-Bench 2.0Source 59.3%—Not comparable
OSWorld-VerifiedSource 66.3%—Not comparable
OSWorldSource 66.3%—Not comparable
Claw-EvalSource 59.6%—Not comparable
QwenClawBenchSource 52.3%—Not comparable
τ³-bench resultsSource 70.2%—Not comparable
VITA-BenchSource 23.3%—Not comparable
DeepPlanningSource 26.4%—Not comparable
ToolathlonSource 43.5%—Not comparable
MCP AtlasSource 42.3%—Not comparable
MCP-TasksSource 71.8%—Not comparable
WideResearchSource 76.4%—Not comparable
CyberGymSource 50.6%—Not comparable
τ²-bench resultsSource 86.3%—Not comparable
Gert LabsSource 64.23%—Not comparable
JobBenchSource 32.3%—Not comparable
Coding
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
SWE-bench VerifiedSource 80.9%—Not comparable
LiveCodeBench v6Source 84.8%—Not comparable
SWE-bench ProSource 57.1%—Not comparable
SWE MultilingualSource 77.5%—Not comparable
NL2RepoSource 43.2%—Not comparable
AA-SciCodeSource 47.0%—Not comparable
BigCodeBenchSource —56.8%Not comparable
HumanEvalSource —69.5%Not comparable
ReasoningClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
LongBench v2Source 64.4%44.7%Claude Opus 4.5 leads
AI-NeedleSource 74%—Not comparable
AA-LCRSource 65.3%—Not comparable
CritPtSource 0.3%—Not comparable
BBHSource —86.9%Not comparable
DROPSource —88.6%Not comparable
HellaSwagSource —85.7%Not comparable
WinoGrandeSource —79.5%Not comparable
CLUEWSCSource —82.2%Not comparable
KnowledgeClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
GPQASource 87%—Not comparable
SuperGPQASource 70.6%46.5%Claude Opus 4.5 leads
MMLU-ProSource 89.5%68.3%Claude Opus 4.5 leads
MMLU-ReduxSource 96.6%89.4%Claude Opus 4.5 leads
C-EvalSource 92.2%92.1%Claude Opus 4.5 leads
HLESource 30.8%—Not comparable
Artificial Analysis Intelligence IndexSource 34.7%—Not comparable
AA-GPQA DiamondSource 81.0%—Not comparable
AA-HLESource 12.9%—Not comparable
AA-Omniscience IndexSource -3.9%—Not comparable
AA-Omniscience AccuracySource 40.7%—Not comparable
AA-Omniscience Hallucination RateSource 75.4%—Not comparable
AA MMLU-ProSource 88.9%—Not comparable
AGIEvalSource —82.6%Not comparable
MMLUSource —88.7%Not comparable
MMMLUSource —88.8%Not comparable
CMMLUSource —90.4%Not comparable
MultiLoKoSource —42.2%Not comparable
SimpleQASource —30.1%Not comparable
FACTS ParametricSource —33.9%Not comparable
TriviaQASource —82.8%Not comparable
Math
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
AIME26Source 95.1%—Not comparable
HMMT Feb 2025Source 92.9%—Not comparable
HMMT Nov 2025Source 93.3%—Not comparable
HMMT Feb 2026Source 85.3%—Not comparable
MMAnswerBenchSource 84.0%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 20.690%—Not comparable
FrontierMath v2 (Tier 4)Source 4.167%—Not comparable
GSM8KSource —90.8%Not comparable
MATHSource —57.4%Not comparable
CMathSource —93.6%Not comparable
Multilingual
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
MMLU-ProXSource 85.7%—Not comparable
NOVA-63Source 56.7%—Not comparable
MGSMSource —85.7%Not comparable
Multimodal
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
MMMU-ProSource 70.6%—Not comparable
MathVisionSource 74.3%—Not comparable
CharXivSource 68.5%—Not comparable
VideoMMMUSource 84.4%—Not comparable
ScreenSpot ProSource 45.7%—Not comparable
V*Source 67.0%—Not comparable
AA-MMMU-ProSource 71.2%—Not comparable
Design Arena WebsiteSource 1277—Not comparable
Inst. Following
BenchmarkClaude Opus 4.5DeepSeek V4 Flash BaseResult
IFEvalSource 90.9%—Not comparable
IFBenchSource 58%—Not comparable
AA-IFBenchSource 43.0%—Not comparable
Frequently Asked Questions (3)

Which is better, Claude Opus 4.5 or DeepSeek V4 Flash Base?

Claude Opus 4.5 and DeepSeek V4 Flash Base are tied on the BenchAlign overall score, so the right pick depends on which category matters most for your use case.

Which is better for knowledge tasks, Claude Opus 4.5 or DeepSeek V4 Flash Base?

Claude Opus 4.5 has the edge for knowledge tasks in this comparison, averaging 58.1 versus 56.4. Inside this category, SuperGPQA is the benchmark that creates the most daylight between them.

Which is better for reasoning, Claude Opus 4.5 or DeepSeek V4 Flash Base?

Claude Opus 4.5 has the edge for reasoning in this comparison, averaging 64.4 versus 44.7. Inside this category, LongBench v2 is the benchmark that creates the most daylight between them.

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