# DeepSeek V4 Flash vs Grok 4.20 (Non-Reasoning)

> DeepSeek V4 Flash is the stronger model overall, scoring 53.6 to 48.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/deepseek-v4-flash-vs-grok-4-20
- Last updated: 2026-10-11
- Shared benchmarks: 35

## Summary

- They share 35 benchmarks with published results for both. DeepSeek V4 Flash scores higher in 5 categories and Grok 4.20 (Non-Reasoning) in 3 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in math, where DeepSeek V4 Flash leads 60.3 to 48.2.
- The biggest single-benchmark swing is ProofBench: 56% for DeepSeek V4 Flash and 14% for Grok 4.20 (Non-Reasoning).
- DeepSeek V4 Flash is cheaper at $0.15 / $0.60 per million input/output tokens, against $1.25 / $2.50 for Grok 4.20 (Non-Reasoning).
- DeepSeek V4 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| Provider | DeepSeek | xAI |
| Noometry Index | 53.6 | 48.6 |
| Rank | 35 | 54 |
| Context | 1M | 1M |
| Input $/M | $0.15 | $1.25 |
| Output $/M | $0.60 | $2.50 |
| Weights | Open | Proprietary |

## Coding

- DeepSeek V4 Flash: 47.9 (#59)
- Grok 4.20 (Non-Reasoning): 42.1 (#112)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena WebDev | 1582 | 1375 |
| WeirdML | 63% | 52.3% |
| LMArena Coding | 1457 | 1459 |
| ALE-Bench | 1,306 | 1,150 |
| FrontierCode | 18.8% | — |
| SciCode | 49.9% | — |

## Agentic & Tool Use

- DeepSeek V4 Flash: —
- Grok 4.20 (Non-Reasoning): 34.4 (#46)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| Terminal-Bench | — | 57.3% |
| τ²-bench Banking | — | 18% |
| LMArena Search | — | 1189 |
| Vending-Bench 2 | — | 4,663 |

## Reasoning

- DeepSeek V4 Flash: 53.7 (#30)
- Grok 4.20 (Non-Reasoning): 52.3 (#32)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| ARC-AGI-2 | 61.4% | 65.1% |
| Kagi LLM Benchmark | 52.2% | 75% |
| NYT Connections (extended) | 89.6% | 85.4% |
| ARC-AGI-1 | 89% | 89.5% |
| Chess Puzzles | 33% | 24% |
| LMArena Hard Prompts | 1444 | 1451 |
| DTBench | 90.9% | 90.1% |
| LMCA | 41.7% | 38.7% |
| Epoch Capabilities Index | 154.49 | 151.98 |
| SimpleBench | 61.1% | — |
| CritPt | 16.6% | — |
| Thematic Generalization | — | 63.8% |
| Mystery Game Puzzles | 34% | — |
| ForecastBench | — | 61.4 |

## Math

- DeepSeek V4 Flash: 60.3 (#37)
- Grok 4.20 (Non-Reasoning): 48.2 (#65)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| FrontierMath (Tiers 1-3) | 57.5% | 44.9% |
| FrontierMath Tier 4 | 24.4% | 17.1% |
| OTIS Mock AIME 2024-2025 | 94.4% | 92.2% |
| ProofBench | 56% | 14% |
| LMArena Math | 1427 | 1455 |
| MathArena Final-Answer Competitions | 76.5% | — |

## Knowledge

- DeepSeek V4 Flash: 55.4 (#48)
- Grok 4.20 (Non-Reasoning): 52.8 (#60)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| GPQA Diamond | 91% | 89.3% |
| SimpleQA Verified | 33.6% | 30.2% |
| LMArena Expert | 1441 | 1439 |

## Multimodal

- DeepSeek V4 Flash: —
- Grok 4.20 (Non-Reasoning): 33.3 (#98)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Vision | — | 1263 |
| Blueprint-Bench 2 | — | 0% |
| LMArena Document | — | 1416 |

## Multilingual

- DeepSeek V4 Flash: 53.0 (#72)
- Grok 4.20 (Non-Reasoning): 54.5 (#40)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Non-English | 1420 | 1441 |
| LMArena Chinese | 1468 | 1481 |
| LMArena French | 1439 | 1476 |
| LMArena German | 1418 | 1465 |
| LMArena Japanese | 1406 | 1449 |
| LMArena Korean | 1384 | 1417 |
| LMArena Russian | 1428 | 1458 |
| LMArena Spanish | 1436 | 1443 |

## Instruction Following

- DeepSeek V4 Flash: 74.9 (#81)
- Grok 4.20 (Non-Reasoning): 74.8 (#83)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Instruction Following | 1421 | 1420 |

## Long Context

- DeepSeek V4 Flash: 43.8 (#85)
- Grok 4.20 (Non-Reasoning): 45.5 (#34)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Longer Query | 1434 | 1437 |
| CL-bench | — | 22.2% |
| CL-bench Life | — | 11.9% |

## Writing & Preference

- DeepSeek V4 Flash: 63.8 (#61)
- Grok 4.20 (Non-Reasoning): 65.7 (#44)

| Benchmark | DeepSeek V4 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Text | 1432 | 1451 |
| LMArena Creative Writing | 1403 | 1438 |
| EQ-Bench Creative Writing | 1559 | 1574 |
| LMArena Multi-Turn | 1449 | 1456 |

## FAQ

### Is DeepSeek V4 Flash better than Grok 4.20 (Non-Reasoning)?

DeepSeek V4 Flash is the stronger model overall, scoring 53.6 to 48.6 on the Noometry Index.

### Which is cheaper, DeepSeek V4 Flash or Grok 4.20 (Non-Reasoning)?

DeepSeek V4 Flash is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; Grok 4.20 (Non-Reasoning) lists at $1.25 and $2.50.

### Is DeepSeek V4 Flash or Grok 4.20 (Non-Reasoning) better for coding?

DeepSeek V4 Flash scores higher on coding benchmarks: 47.9 versus 42.1 in the Noometry coding category.

### Which has the bigger context window?

Both accept 1M tokens.

### How many benchmarks do DeepSeek V4 Flash and Grok 4.20 (Non-Reasoning) share?

35 benchmarks have published results for both models. DeepSeek V4 Flash has 41 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.