Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
GPT-5.5 Pro
100
Grok 4.3
79
Pick GPT-5.5 Pro if you want the stronger benchmark profile. Grok 4.3 only becomes the better choice if you want the cheaper token bill.
Knowledge
+3.3 difference
GPT-5.5 Pro
Grok 4.3
$30 / $180
$1.25 / $2.5
N/A
209 t/s
N/A
12.36s
1M
1M
Pick GPT-5.5 Pro if you want the stronger benchmark profile. Grok 4.3 only becomes the better choice if you want the cheaper token bill.
GPT-5.5 Pro is clearly ahead on the provisional aggregate, 100 to 79. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5 Pro's sharpest advantage is in knowledge, where it averages 57.2 against 53.9. The single biggest benchmark swing on the page is HLE, 57.2% to 35%.
GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $1.25 input / $2.50 output per 1M tokens for Grok 4.3. That is roughly 72.0x on output cost alone.
GPT-5.5 Pro is ahead on BenchLM's provisional leaderboard, 100 to 79. The biggest single separator in this matchup is HLE, where the scores are 57.2% and 35%.
GPT-5.5 Pro has the edge for knowledge tasks in this comparison, averaging 57.2 versus 53.9. Inside this category, HLE is the benchmark that creates the most daylight between them.
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