Model comparison
GLM-4.5-Air vs Step 3.5 Flash
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 38.9 on the Noometry Index.
Last verified . 17 shared benchmarks.
StepFunSummary
- They share 17 benchmarks with published results for both. GLM-4.5-Air scores higher in 1 category and Step 3.5 Flash in 7 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in coding, where Step 3.5 Flash leads 42.4 to 33.3.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $0.20 / $1.10 for GLM-4.5-Air.
- Step 3.5 Flash accepts more context: 256K tokens versus 131K.
Side by side
| GLM-4.5-Air | Step 3.5 Flash | |
|---|---|---|
| Provider | Z.ai (Zhipu) | StepFun |
| Noometry Index | 38.9 | 42.3 |
| Released | 2025-07-20 | 2026-01-29 |
| Weights | Open | Open |
| Context window | 131K | 256K |
| Max output | 98K | 256K |
| Input $ / M tokens | $0.20 | $0.10 |
| Output $ / M tokens | $1.10 | $0.30 |
| Results tracked | 27 | 19 |
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Category by category
Coding Step 3.5 Flash leads
GLM-4.5-Air: 33.3 (#259), Step 3.5 Flash: 42.4 (#105)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1397 | 1436 |
| GSO | 2.9% | — |
Reasoning GLM-4.5-Air leads
GLM-4.5-Air: 24.1 (#166), Step 3.5 Flash: 22.2 (#202)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Hard Prompts | 1379 | 1411 |
| Kagi LLM Benchmark | 43% | — |
| NYT Connections (extended) | — | 28.4% |
| ForecastBench | 59.2 | — |
Math Step 3.5 Flash leads
GLM-4.5-Air: 36.2 (#170), Step 3.5 Flash: 42.6 (#84)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Math | 1396 | 1408 |
| MathArena Final-Answer Competitions | — | 66.8% |
| Omni-MATH | 39.1% | — |
Knowledge Step 3.5 Flash leads
GLM-4.5-Air: 35.0 (#191), Step 3.5 Flash: 39.6 (#132)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1370 | 1421 |
| Humanity's Last Exam | 8.1% | — |
| MMLU-Pro | 76.2% | — |
| Vectara Hallucination Rate | 9.3% | — |
| GPQA (HELM) | 59.4% | — |
Multilingual Step 3.5 Flash leads
GLM-4.5-Air: 49.1 (#135), Step 3.5 Flash: 50.5 (#119)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1366 | 1385 |
| LMArena Chinese | 1426 | 1447 |
| LMArena French | 1399 | 1421 |
| LMArena German | 1377 | 1405 |
| LMArena Japanese | 1348 | 1354 |
| LMArena Korean | 1308 | 1352 |
| LMArena Russian | 1373 | 1385 |
| LMArena Spanish | 1386 | 1419 |
Instruction Following Step 3.5 Flash leads
GLM-4.5-Air: 69.6 (#171), Step 3.5 Flash: 73.1 (#124)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1354 | 1385 |
| IFEval | 81.2% | — |
Long Context Step 3.5 Flash leads
GLM-4.5-Air: 41.6 (#135), Step 3.5 Flash: 42.8 (#117)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1366 | 1402 |
Writing & Preference Step 3.5 Flash leads
GLM-4.5-Air: 55.9 (#139), Step 3.5 Flash: 58.8 (#113)
| Benchmark | GLM-4.5-Air | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1384 | 1403 |
| LMArena Creative Writing | 1343 | 1357 |
| LMArena Multi-Turn | 1371 | 1405 |
| WildBench | 78.9% | — |
Frequently asked questions
Is GLM-4.5-Air better than Step 3.5 Flash?
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 38.9 on the Noometry Index.
Which is cheaper, GLM-4.5-Air or Step 3.5 Flash?
Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; GLM-4.5-Air lists at $0.20 and $1.10.
Is GLM-4.5-Air or Step 3.5 Flash better for coding?
Step 3.5 Flash scores higher on coding benchmarks: 42.4 versus 33.3 in the Noometry coding category.
Which has the bigger context window?
Step 3.5 Flash does, with 256K tokens against 131K.
How many benchmarks do GLM-4.5-Air and Step 3.5 Flash share?
17 benchmarks have published results for both models. GLM-4.5-Air has 27 scored results on Noometry and Step 3.5 Flash has 19.