Model comparison
GLM-4.5 vs Grok 4 Fast
GLM-4.5 is the stronger model overall, scoring 42.0 to 39.4 on the Noometry Index.
Last verified . 20 shared benchmarks.
Summary
- They share 20 benchmarks with published results for both. GLM-4.5 scores higher in 6 categories and Grok 4 Fast in 2 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 38.2.
- The biggest single-benchmark swing is Fiction.LiveBench: 58.3% for GLM-4.5 and 94.4% for Grok 4 Fast.
- GLM-4.5 has downloadable open weights; the other is API-only.
Side by side
| GLM-4.5 | Grok 4 Fast | |
|---|---|---|
| Provider | Z.ai (Zhipu) | xAI |
| Noometry Index | 42.0 | 39.4 |
| Released | 2025-07-27 | 2025-09-19 |
| Weights | Open | Proprietary |
| Context window | 131K | — |
| Max output | 98K | — |
| Input $ / M tokens | $0.60 | — |
| Output $ / M tokens | $2.20 | — |
| Results tracked | 27 | 30 |
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Category by category
Coding GLM-4.5 leads
GLM-4.5: 41.4 (#125), Grok 4 Fast: 32.5 (#271)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| WeirdML | 40.6% | 42.9% |
| LMArena Coding | 1434 | 1429 |
| SWE-bench Verified (bash only) | 54.2% | — |
| LMArena WebDev | — | 1159 |
| ALE-Bench | 344.82 | — |
| AlgoTune | 1.52 | — |
Agentic & Tool Use Not comparable
GLM-4.5: —, Grok 4 Fast: 29.5 (#86)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| τ²-bench Banking | — | 15.7% |
| Cybench | — | 30% |
| LMArena Search | — | 1171 |
Reasoning GLM-4.5 leads
GLM-4.5: 28.6 (#100), Grok 4 Fast: 22.2 (#201)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| Kagi LLM Benchmark | 57.9% | 66.1% |
| LMArena Hard Prompts | 1429 | 1412 |
| ARC-AGI-2 | — | 5.3% |
| ARC-AGI-1 | — | 48.5% |
| DTBench | — | 82.7% |
| Epoch Capabilities Index | — | 144.2 |
| ForecastBench | — | 60.5 |
Math Too close to call
GLM-4.5: 39.0 (#116), Grok 4 Fast: 38.9 (#123)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1427 | 1419 |
Knowledge GLM-4.5 leads
GLM-4.5: 35.9 (#179), Grok 4 Fast: 32.0 (#214)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1433 | 1411 |
| Humanity's Last Exam | 8.3% | — |
| Confabulations | 11.3% | — |
| Vectara Hallucination Rate | — | 19.7% |
Multilingual GLM-4.5 leads
GLM-4.5: 52.8 (#77), Grok 4 Fast: 51.3 (#111)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1417 | 1396 |
| LMArena Chinese | 1465 | 1457 |
| LMArena French | 1418 | 1431 |
| LMArena German | 1407 | 1383 |
| LMArena Japanese | 1415 | 1352 |
| LMArena Korean | 1380 | 1357 |
| LMArena Russian | 1414 | 1389 |
| LMArena Spanish | 1454 | 1415 |
Instruction Following Too close to call
GLM-4.5: 74.1 (#104), Grok 4 Fast: 73.2 (#121)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1404 | 1387 |
Long Context Grok 4 Fast leads
GLM-4.5: 38.2 (#201), Grok 4 Fast: 63.2 (#3)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| Fiction.LiveBench | 58.3% | 94.4% |
| LMArena Longer Query | 1412 | 1415 |
Writing & Preference Grok 4 Fast leads
GLM-4.5: 57.5 (#127), Grok 4 Fast: 60.0 (#102)
| Benchmark | GLM-4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1430 | 1407 |
| LMArena Creative Writing | 1395 | 1387 |
| LMArena Multi-Turn | 1415 | 1414 |
| Short-Story Creative Writing | 73.4% | — |
| EQ-Bench Creative Writing | 1343 | — |
Frequently asked questions
Is GLM-4.5 better than Grok 4 Fast?
GLM-4.5 is the stronger model overall, scoring 42.0 to 39.4 on the Noometry Index.
Is GLM-4.5 or Grok 4 Fast better for coding?
GLM-4.5 scores higher on coding benchmarks: 41.4 versus 32.5 in the Noometry coding category.
How many benchmarks do GLM-4.5 and Grok 4 Fast share?
20 benchmarks have published results for both models. GLM-4.5 has 27 scored results on Noometry and Grok 4 Fast has 30.