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 Base
31
Verified leaderboard positions: Claude Opus 4.5 #9 · DeepSeek V4 Flash Base unranked
Pick Claude Opus 4.5 if you want the stronger benchmark profile. DeepSeek V4 Flash Base only becomes the better choice if you need the larger 1M context window.
Reasoning
+19.7 difference
Knowledge
+14.0 difference
Multilingual
Claude Opus 4.5
DeepSeek V4 Flash Base
$5 / $25
$null / $null
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 Base only becomes the better choice if you need the larger 1M context window.
Claude Opus 4.5 is clearly ahead on the provisional aggregate, 78 to 31. 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 reasoning, where it averages 64.4 against 44.7. The single biggest benchmark swing on the page is SuperGPQA, 70.6% to 46.5%.
DeepSeek V4 Flash Base 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 31. The biggest single separator in this matchup is SuperGPQA, where the scores are 70.6% and 46.5%.
Claude Opus 4.5 has the edge for knowledge tasks in this comparison, averaging 66.2 versus 52.2. Inside this category, SuperGPQA is the benchmark that creates the most daylight between them.
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.
Claude Opus 4.5 and DeepSeek V4 Flash Base are effectively tied for multilingual tasks here, both landing at 85.7 on average.
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