Model comparison
Grok 4 Fast vs Solar Pro4
Solar Pro4 is the stronger model overall, scoring 42.1 to 39.4 on the Noometry Index.
Last verified . 18 shared benchmarks.
UpstageSummary
- They share 18 benchmarks with published results for both. Grok 4 Fast scores higher in 5 categories and Solar Pro4 in 3 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 42.1.
Side by side
| Grok 4 Fast | Solar Pro4 | |
|---|---|---|
| Provider | xAI | Upstage |
| Noometry Index | 39.4 | 42.1 |
| Released | 2025-09-19 | 2026-08-06 |
| Weights | Proprietary | Proprietary |
| Context window | — | 524K |
| Max output | — | 131K |
| Input $ / M tokens | — | $0.30 |
| Output $ / M tokens | — | $1.20 |
| Results tracked | 30 | 18 |
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Category by category
Coding Solar Pro4 leads
Grok 4 Fast: 32.5 (#271), Solar Pro4: 40.1 (#149)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena WebDev | 1159 | 1371 |
| LMArena Coding | 1429 | 1437 |
| WeirdML | 42.9% | — |
Agentic & Tool Use Not comparable
Grok 4 Fast: 29.5 (#86), Solar Pro4: —
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |
Reasoning Solar Pro4 leads
Grok 4 Fast: 22.2 (#201), Solar Pro4: 28.5 (#104)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena Hard Prompts | 1412 | 1399 |
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| ARC-AGI-1 | 48.5% | — |
| DTBench | 82.7% | — |
| Epoch Capabilities Index | 144.2 | — |
| ForecastBench | 60.5 | — |
Math Too close to call
Grok 4 Fast: 38.9 (#123), Solar Pro4: 38.8 (#128)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena Math | 1419 | 1416 |
Knowledge Solar Pro4 leads
Grok 4 Fast: 32.0 (#214), Solar Pro4: 39.8 (#129)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena Expert | 1411 | 1427 |
| Vectara Hallucination Rate | 19.7% | — |
Multilingual Grok 4 Fast leads
Grok 4 Fast: 51.3 (#111), Solar Pro4: 48.7 (#139)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena Non-English | 1396 | 1361 |
| LMArena Chinese | 1457 | 1415 |
| LMArena French | 1431 | 1397 |
| LMArena German | 1383 | 1364 |
| LMArena Japanese | 1352 | 1309 |
| LMArena Korean | 1357 | 1382 |
| LMArena Russian | 1389 | 1360 |
| LMArena Spanish | 1415 | 1401 |
Instruction Following Too close to call
Grok 4 Fast: 73.2 (#121), Solar Pro4: 72.7 (#132)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena Instruction Following | 1387 | 1377 |
Long Context Grok 4 Fast leads
Grok 4 Fast: 63.2 (#3), Solar Pro4: 42.1 (#130)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena Longer Query | 1415 | 1381 |
| Fiction.LiveBench | 94.4% | — |
Writing & Preference Grok 4 Fast leads
Grok 4 Fast: 60.0 (#102), Solar Pro4: 56.5 (#138)
| Benchmark | Grok 4 Fast | Solar Pro4 |
|---|---|---|
| LMArena Text | 1407 | 1386 |
| LMArena Creative Writing | 1387 | 1316 |
| LMArena Multi-Turn | 1414 | 1385 |
Frequently asked questions
Is Grok 4 Fast better than Solar Pro4?
Solar Pro4 is the stronger model overall, scoring 42.1 to 39.4 on the Noometry Index.
Is Grok 4 Fast or Solar Pro4 better for coding?
Solar Pro4 scores higher on coding benchmarks: 40.1 versus 32.5 in the Noometry coding category.
How many benchmarks do Grok 4 Fast and Solar Pro4 share?
18 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Solar Pro4 has 18.