Model comparison
GLM-5.1 vs Step 3.5 Flash
GLM-5.1 is the stronger model overall, scoring 47.8 to 42.3 on the Noometry Index. Step 3.5 Flash costs 14× less per token, which makes it the better buy when GLM-5.1's lead doesn't matter for your workload.
Last verified . 19 shared benchmarks.
StepFunSummary
- They share 19 benchmarks with published results for both. GLM-5.1 scores higher in 8 categories and Step 3.5 Flash in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GLM-5.1 leads 39.1 to 22.2.
- The biggest single-benchmark swing is NYT Connections (extended): 77.7% for GLM-5.1 and 28.4% for Step 3.5 Flash.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $1.40 / $4.40 for GLM-5.1.
- Step 3.5 Flash accepts more context: 256K tokens versus 200K.
Side by side
| GLM-5.1 | Step 3.5 Flash | |
|---|---|---|
| Provider | Z.ai (Zhipu) | StepFun |
| Noometry Index | 47.8 | 42.3 |
| Released | 2026-04-07 | 2026-01-29 |
| Weights | Open | Open |
| Context window | 200K | 256K |
| Max output | 131K | 256K |
| Input $ / M tokens | $1.40 | $0.10 |
| Output $ / M tokens | $4.40 | $0.30 |
| Results tracked | 41 | 19 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding GLM-5.1 leads
GLM-5.1: 48.7 (#55), Step 3.5 Flash: 42.4 (#105)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1485 | 1436 |
| SWE-bench Verified | 74.2% | — |
| LMArena WebDev | 1508 | — |
| SciCode | 43.8% | — |
| WeirdML | 57.1% | — |
| ALE-Bench | 887.1 | — |
Agentic & Tool Use Not comparable
GLM-5.1: 24.9 (#113), Step 3.5 Flash: —
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| APEX-Agents | 40.9% | — |
| ExploitBench | 18.1% | — |
| GBAEval | 0% | — |
| Vending-Bench 2 | 5,634 | — |
Reasoning GLM-5.1 leads
GLM-5.1: 39.1 (#60), Step 3.5 Flash: 22.2 (#202)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| NYT Connections (extended) | 77.7% | 28.4% |
| LMArena Hard Prompts | 1472 | 1411 |
| SimpleBench | 55.1% | — |
| CritPt | 4.6% | — |
| Chess Puzzles | 19% | — |
| Thematic Generalization | 69.8% | — |
| Epoch Capabilities Index | 149.84 | — |
Math GLM-5.1 leads
GLM-5.1: 49.7 (#60), Step 3.5 Flash: 42.6 (#84)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| MathArena Final-Answer Competitions | 67.1% | 66.8% |
| LMArena Math | 1473 | 1408 |
| FrontierMath (Tiers 1-3) | 36.8% | — |
| OTIS Mock AIME 2024-2025 | 93.3% | — |
| ProofBench | 22.2% | — |
| FrontierMath (Feb 2025 set) | 33.4% | — |
| FrontierMath Tier 4 (v1) | 12.5% | — |
Knowledge GLM-5.1 leads
GLM-5.1: 54.9 (#50), Step 3.5 Flash: 39.6 (#132)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1476 | 1421 |
| GPQA Diamond | 89.9% | — |
| SimpleQA Verified | 34% | — |
Multilingual GLM-5.1 leads
GLM-5.1: 55.0 (#36), Step 3.5 Flash: 50.5 (#119)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1447 | 1385 |
| LMArena Chinese | 1515 | 1447 |
| LMArena French | 1474 | 1421 |
| LMArena German | 1465 | 1405 |
| LMArena Japanese | 1434 | 1354 |
| LMArena Korean | 1418 | 1352 |
| LMArena Russian | 1454 | 1385 |
| LMArena Spanish | 1469 | 1419 |
Instruction Following GLM-5.1 leads
GLM-5.1: 76.3 (#42), Step 3.5 Flash: 73.1 (#124)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1451 | 1385 |
Long Context GLM-5.1 leads
GLM-5.1: 44.9 (#53), Step 3.5 Flash: 42.8 (#117)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1466 | 1402 |
Writing & Preference GLM-5.1 leads
GLM-5.1: 66.9 (#31), Step 3.5 Flash: 58.8 (#113)
| Benchmark | GLM-5.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1461 | 1403 |
| LMArena Creative Writing | 1453 | 1357 |
| LMArena Multi-Turn | 1472 | 1405 |
| EQ-Bench Creative Writing | 1592 | — |
Frequently asked questions
Is GLM-5.1 better than Step 3.5 Flash?
GLM-5.1 is the stronger model overall, scoring 47.8 to 42.3 on the Noometry Index. Step 3.5 Flash costs 14× less per token, which makes it the better buy when GLM-5.1's lead doesn't matter for your workload.
Which is cheaper, GLM-5.1 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-5.1 lists at $1.40 and $4.40.
Is GLM-5.1 or Step 3.5 Flash better for coding?
GLM-5.1 scores higher on coding benchmarks: 48.7 versus 42.4 in the Noometry coding category.
Which has the bigger context window?
Step 3.5 Flash does, with 256K tokens against 200K.
How many benchmarks do GLM-5.1 and Step 3.5 Flash share?
19 benchmarks have published results for both models. GLM-5.1 has 41 scored results on Noometry and Step 3.5 Flash has 19.