Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Fable 5
96
GPT-5.4 nano
59
Verified leaderboard positions: Claude Fable 5 #2 · GPT-5.4 nano unranked
Pick Claude Fable 5 if you want the stronger benchmark profile. GPT-5.4 nano only becomes the better choice if you want the cheaper token bill.
Agentic
+42.3 difference
Knowledge
+21.6 difference
Multimodal
+26.3 difference
Claude Fable 5
GPT-5.4 nano
$10 / $50
$0.2 / $1.25
N/A
191 t/s
N/A
3.64s
1M+
400K
Pick Claude Fable 5 if you want the stronger benchmark profile. GPT-5.4 nano only becomes the better choice if you want the cheaper token bill.
Claude Fable 5 is clearly ahead on the provisional aggregate, 96 to 59. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Fable 5's sharpest advantage is in agentic, where it averages 85.2 against 42.9. The single biggest benchmark swing on the page is OSWorld-Verified, 85% to 39%.
Claude Fable 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $0.20 input / $1.25 output per 1M tokens for GPT-5.4 nano. That is roughly 40.0x on output cost alone. Claude Fable 5 gives you the larger context window at 1M+, compared with 400K for GPT-5.4 nano.
Claude Fable 5 is ahead on BenchLM's provisional leaderboard, 96 to 59. The biggest single separator in this matchup is OSWorld-Verified, where the scores are 85% and 39%.
Claude Fable 5 has the edge for knowledge tasks in this comparison, averaging 74.8 versus 53.2. Inside this category, HLE w/o tools is the benchmark that creates the most daylight between them.
Claude Fable 5 has the edge for agentic tasks in this comparison, averaging 85.2 versus 42.9. Inside this category, GDPval-AA is the benchmark that creates the most daylight between them.
Claude Fable 5 has the edge for multimodal and grounded tasks in this comparison, averaging 92.4 versus 66.1. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
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