Head-to-head comparison across 4benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
GPT-5.4
89
GPT-5.5
91
Verified leaderboard positions: GPT-5.4 #16 · GPT-5.5 #5
Pick GPT-5.5 if you want the stronger benchmark profile. GPT-5.4 only becomes the better choice if multimodal & grounded is the priority or you want the cheaper token bill.
Agentic
+4.5 difference
Coding
+0.9 difference
Knowledge
+0.3 difference
Multimodal
+2.3 difference
GPT-5.4
GPT-5.5
$2.5 / $15
$5 / $30
74 t/s
N/A
151.79s
N/A
1.05M
1M
Pick GPT-5.5 if you want the stronger benchmark profile. GPT-5.4 only becomes the better choice if multimodal & grounded is the priority or you want the cheaper token bill.
GPT-5.5 has the cleaner provisional overall profile here, landing at 91 versus 89. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
GPT-5.5's sharpest advantage is in agentic, where it averages 81.5 against 77. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 75.1% to 82%. GPT-5.4 does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.
GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $2.50 input / $15.00 output per 1M tokens for GPT-5.4. That is roughly 2.0x on output cost alone. GPT-5.4 gives you the larger context window at 1.05M, compared with 1M for GPT-5.5.
GPT-5.5 is ahead on BenchLM's provisional leaderboard, 91 to 89. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 75.1% and 82%.
GPT-5.5 has the edge for knowledge tasks in this comparison, averaging 66.4 versus 66.1. Inside this category, AA-Omniscience Index is the benchmark that creates the most daylight between them.
GPT-5.5 has the edge for coding in this comparison, averaging 58.6 versus 57.7. Inside this category, Terminal-Bench Hard 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 77. Inside this category, GDPval-AA is the benchmark that creates the most daylight between them.
GPT-5.4 has the edge for multimodal and grounded tasks in this comparison, averaging 72.7 versus 70.4. Inside this category, AA-MMMU-Pro is the benchmark that creates the most daylight between them.
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