Model comparison
GPT-5.5 Pro vs Muse Glimmer
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 41.7 on the Noometry Index.
Last verified . 1 shared benchmarks.
MetaSummary
- They share 1 benchmark with published results for both. GPT-5.5 Pro scores higher in 3 categories and Muse Glimmer in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5.5 Pro leads 73.3 to 25.7.
- The biggest single-benchmark swing is CritPt: 30.6% for GPT-5.5 Pro and 2.6% for Muse Glimmer.
- Muse Glimmer has downloadable open weights; the other is API-only.
Side by side
| GPT-5.5 Pro | Muse Glimmer | |
|---|---|---|
| Provider | OpenAI | Meta |
| Noometry Index | 64.3 | 41.7 |
| Released | 2026-04-23 | 2026-08-10 |
| Weights | Proprietary | Open |
| Context window | 1.05M | — |
| Max output | 128K | — |
| Input $ / M tokens | $30 | — |
| Output $ / M tokens | $180 | — |
| Results tracked | 14 | 15 |
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Category by category
Coding Not comparable
GPT-5.5 Pro: —, Muse Glimmer: 40.4 (#142)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| LMArena WebDev | — | 1355 |
| SciCode | — | 44.9% |
| LMArena Coding | — | 1416 |
Reasoning GPT-5.5 Pro leads
GPT-5.5 Pro: 73.3 (#10), Muse Glimmer: 25.7 (#144)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| CritPt | 30.6% | 2.6% |
| ARC-AGI-2 | 84.6% | — |
| SimpleBench | 76.9% | — |
| ARC-AGI-1 | 96.5% | — |
| Chess Puzzles | 64% | — |
| LMArena Hard Prompts | — | 1396 |
| DTBench | 96% | — |
| LMCA | 53.9% | — |
| Epoch Capabilities Index | 162.07 | — |
Math GPT-5.5 Pro leads
GPT-5.5 Pro: 84.0 (#10), Muse Glimmer: 38.8 (#125)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| FrontierMath (Tiers 1-3) | 87.7% | — |
| FrontierMath Tier 4 | 78% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| LMArena Math | — | 1417 |
| 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), Muse Glimmer: 38.5 (#143)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| GPQA Diamond | 93.9% | — |
| LMArena Expert | — | 1386 |
Multilingual Not comparable
GPT-5.5 Pro: —, Muse Glimmer: 50.5 (#122)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| LMArena Non-English | — | 1384 |
| LMArena Chinese | — | 1412 |
| LMArena Russian | — | 1390 |
Instruction Following Not comparable
GPT-5.5 Pro: —, Muse Glimmer: 72.6 (#135)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| LMArena Instruction Following | — | 1375 |
Long Context Not comparable
GPT-5.5 Pro: —, Muse Glimmer: 42.1 (#129)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| LMArena Longer Query | — | 1382 |
Writing & Preference Not comparable
GPT-5.5 Pro: —, Muse Glimmer: 57.5 (#126)
| Benchmark | GPT-5.5 Pro | Muse Glimmer |
|---|---|---|
| LMArena Text | — | 1389 |
| LMArena Creative Writing | — | 1339 |
| LMArena Multi-Turn | — | 1399 |
Frequently asked questions
Is GPT-5.5 Pro better than Muse Glimmer?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 41.7 on the Noometry Index.
How many benchmarks do GPT-5.5 Pro and Muse Glimmer share?
1 benchmark has published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and Muse Glimmer has 15.