Model comparison
Grok Build 0.1 vs Step 3.5 Flash
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 36.4 on the Noometry Index.
Last verified . 0 shared benchmarks.
StepFunSummary
- The widest gap is in reasoning, where Grok Build 0.1 leads 32.2 to 22.2.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $1 / $2 for Grok Build 0.1.
- Step 3.5 Flash has downloadable open weights; the other is API-only.
Side by side
| Grok Build 0.1 | Step 3.5 Flash | |
|---|---|---|
| Provider | xAI | StepFun |
| Noometry Index | 36.4 | 42.3 |
| Released | 2026-04-16 | 2026-01-29 |
| Weights | Proprietary | Open |
| Context window | 256K | 256K |
| Max output | 256K | 256K |
| Input $ / M tokens | $1 | $0.10 |
| Output $ / M tokens | $2 | $0.30 |
| Results tracked | 3 | 19 |
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Category by category
Coding Too close to call
Grok Build 0.1: 43.1 (#91), Step 3.5 Flash: 42.4 (#105)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| SciCode | 50.2% | — |
| LMArena Coding | — | 1436 |
Agentic & Tool Use Not comparable
Grok Build 0.1: 22.7 (#129), Step 3.5 Flash: —
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| GBAEval | 2.4% | — |
Reasoning Grok Build 0.1 leads
Grok Build 0.1: 32.2 (#77), Step 3.5 Flash: 22.2 (#202)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| NYT Connections (extended) | — | 28.4% |
| CritPt | 9.1% | — |
| LMArena Hard Prompts | — | 1411 |
Math Not comparable
Grok Build 0.1: —, Step 3.5 Flash: 42.6 (#84)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| MathArena Final-Answer Competitions | — | 66.8% |
| LMArena Math | — | 1408 |
Knowledge Not comparable
Grok Build 0.1: —, Step 3.5 Flash: 39.6 (#132)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | — | 1421 |
Multilingual Not comparable
Grok Build 0.1: —, Step 3.5 Flash: 50.5 (#119)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | — | 1385 |
| LMArena Chinese | — | 1447 |
| LMArena French | — | 1421 |
| LMArena German | — | 1405 |
| LMArena Japanese | — | 1354 |
| LMArena Korean | — | 1352 |
| LMArena Russian | — | 1385 |
| LMArena Spanish | — | 1419 |
Instruction Following Not comparable
Grok Build 0.1: —, Step 3.5 Flash: 73.1 (#124)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | — | 1385 |
Long Context Not comparable
Grok Build 0.1: —, Step 3.5 Flash: 42.8 (#117)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | — | 1402 |
Writing & Preference Not comparable
Grok Build 0.1: —, Step 3.5 Flash: 58.8 (#113)
| Benchmark | Grok Build 0.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Text | — | 1403 |
| LMArena Creative Writing | — | 1357 |
| LMArena Multi-Turn | — | 1405 |
Frequently asked questions
Is Grok Build 0.1 better than Step 3.5 Flash?
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 36.4 on the Noometry Index.
Which is cheaper, Grok Build 0.1 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; Grok Build 0.1 lists at $1 and $2.
Is Grok Build 0.1 or Step 3.5 Flash better for coding?
They score almost the same on coding (43.1 vs 42.4); test both on your own repository before choosing.
Which has the bigger context window?
Both accept 256K tokens.
How many benchmarks do Grok Build 0.1 and Step 3.5 Flash share?
0 benchmarks have published results for both models. Grok Build 0.1 has 3 scored results on Noometry and Step 3.5 Flash has 19.