Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
GPT-5.4 nano
59
GPT-5.5
91
Verified leaderboard positions: GPT-5.4 nano unranked · GPT-5.5 #5
Pick GPT-5.5 if you want the stronger benchmark profile. GPT-5.4 nano only becomes the better choice if you want the cheaper token bill.
Agentic
+38.6 difference
Knowledge
+13.2 difference
Multimodal
+4.3 difference
GPT-5.4 nano
GPT-5.5
$0.2 / $1.25
$5 / $30
191 t/s
N/A
3.64s
N/A
400K
1M
Pick GPT-5.5 if you want the stronger benchmark profile. GPT-5.4 nano only becomes the better choice if you want the cheaper token bill.
GPT-5.5 is clearly ahead on the provisional aggregate, 91 to 59. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5's sharpest advantage is in agentic, where it averages 81.5 against 42.9. The single biggest benchmark swing on the page is OSWorld-Verified, 39% to 78.7%.
GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $0.20 input / $1.25 output per 1M tokens for GPT-5.4 nano. That is roughly 24.0x on output cost alone. GPT-5.5 gives you the larger context window at 1M, compared with 400K for GPT-5.4 nano.
GPT-5.5 is ahead on BenchLM's provisional leaderboard, 91 to 59. The biggest single separator in this matchup is OSWorld-Verified, where the scores are 39% and 78.7%.
GPT-5.5 has the edge for knowledge tasks in this comparison, averaging 66.4 versus 53.2. Inside this category, AA-Omniscience Index is the benchmark that creates the most daylight between them.
GPT-5.5 has the edge for agentic tasks in this comparison, averaging 81.5 versus 42.9. Inside this category, GDPval-AA is the benchmark that creates the most daylight between them.
GPT-5.5 has the edge for multimodal and grounded tasks in this comparison, averaging 70.4 versus 66.1. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
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