Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Opus 4.5
78
DeepSeek V4 Flash
59
Verified leaderboard positions: Claude Opus 4.5 #9 · DeepSeek V4 Flash #23
Pick Claude Opus 4.5 if you want the stronger benchmark profile. DeepSeek V4 Flash only becomes the better choice if you want the cheaper token bill or you need the larger 1M context window.
Agentic
+13.4 difference
Coding
+8.8 difference
Knowledge
+21.0 difference
Claude Opus 4.5
DeepSeek V4 Flash
$5 / $25
$0.14 / $0.28
46 t/s
N/A
1.01s
N/A
200K
1M
Pick Claude Opus 4.5 if you want the stronger benchmark profile. DeepSeek V4 Flash only becomes the better choice if you want the cheaper token bill or you need the larger 1M context window.
Claude Opus 4.5 is clearly ahead on the provisional aggregate, 78 to 59. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Opus 4.5's sharpest advantage is in knowledge, where it averages 66.2 against 45.2. The single biggest benchmark swing on the page is HLE, 30.8% to 8.1%.
Claude Opus 4.5 is also the more expensive model on tokens at $5.00 input / $25.00 output per 1M tokens, versus $0.14 input / $0.28 output per 1M tokens for DeepSeek V4 Flash. That is roughly 89.3x on output cost alone. DeepSeek V4 Flash gives you the larger context window at 1M, compared with 200K for Claude Opus 4.5.
Claude Opus 4.5 is ahead on BenchLM's provisional leaderboard, 78 to 59. The biggest single separator in this matchup is HLE, where the scores are 30.8% and 8.1%.
Claude Opus 4.5 has the edge for knowledge tasks in this comparison, averaging 66.2 versus 45.2. Inside this category, HLE is the benchmark that creates the most daylight between them.
Claude Opus 4.5 has the edge for coding in this comparison, averaging 65.9 versus 57.1. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
Claude Opus 4.5 has the edge for agentic tasks in this comparison, averaging 62.5 versus 49.1. Inside this category, MCP Atlas is the benchmark that creates the most daylight between them.
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