Model comparison
GPT-5.5 Pro vs Step 2 16k Exp 202412
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 39.2 on the Noometry Index.
Last verified . 0 shared benchmarks.
StepFunSummary
- The widest gap is in math, where GPT-5.5 Pro leads 84.0 to 36.3.
Side by side
| GPT-5.5 Pro | Step 2 16k Exp 202412 | |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 64.3 | 39.2 |
| Released | 2026-04-23 | — |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | — |
| Max output | 128K | — |
| Input $ / M tokens | $30 | — |
| Output $ / M tokens | $180 | — |
| Results tracked | 14 | 12 |
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Category by category
Coding Not comparable
GPT-5.5 Pro: —, Step 2 16k Exp 202412: 38.5 (#174)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Coding | — | 1316 |
Reasoning GPT-5.5 Pro leads
GPT-5.5 Pro: 73.3 (#10), Step 2 16k Exp 202412: 25.9 (#142)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| ARC-AGI-2 | 84.6% | — |
| SimpleBench | 76.9% | — |
| ARC-AGI-1 | 96.5% | — |
| CritPt | 30.6% | — |
| Chess Puzzles | 64% | — |
| LMArena Hard Prompts | — | 1299 |
| DTBench | 96% | — |
| LMCA | 53.9% | — |
| Epoch Capabilities Index | 162.07 | — |
Math GPT-5.5 Pro leads
GPT-5.5 Pro: 84.0 (#10), Step 2 16k Exp 202412: 36.3 (#169)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 87.7% | — |
| FrontierMath Tier 4 | 78% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| LMArena Math | — | 1304 |
| FrontierMath (Feb 2025 set) | 52.4% | — |
| FrontierMath Tier 4 (v1) | 39.6% | — |
Knowledge GPT-5.5 Pro leads
GPT-5.5 Pro: 64.1 (#19), Step 2 16k Exp 202412: 35.2 (#187)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| GPQA Diamond | 93.9% | — |
| LMArena Expert | — | 1279 |
Multilingual Not comparable
GPT-5.5 Pro: —, Step 2 16k Exp 202412: 43.7 (#181)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Non-English | — | 1290 |
| LMArena Chinese | — | 1331 |
| LMArena Russian | — | 1324 |
Instruction Following Not comparable
GPT-5.5 Pro: —, Step 2 16k Exp 202412: 67.9 (#192)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Instruction Following | — | 1287 |
Long Context Not comparable
GPT-5.5 Pro: —, Step 2 16k Exp 202412: 39.7 (#170)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Longer Query | — | 1307 |
Writing & Preference Not comparable
GPT-5.5 Pro: —, Step 2 16k Exp 202412: 52.3 (#173)
| Benchmark | GPT-5.5 Pro | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Text | — | 1321 |
| LMArena Creative Writing | — | 1328 |
| LMArena Multi-Turn | — | 1292 |
Frequently asked questions
Is GPT-5.5 Pro better than Step 2 16k Exp 202412?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 39.2 on the Noometry Index.
How many benchmarks do GPT-5.5 Pro and Step 2 16k Exp 202412 share?
0 benchmarks have published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and Step 2 16k Exp 202412 has 12.