# Grok 4.1 Fast (Reasoning) vs Nemotron Diffusion 8B (pst2154, optimized vLLM)

> Side-by-side benchmark comparison for Grok 4.1 Fast (Reasoning) and Nemotron Diffusion 8B (pst2154, optimized vLLM) across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/grok-4-1-fast-reasoning-vs-jevbench-nemotron-diffusion-8b
- Last updated: September 30, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for Grok 4.1 Fast (Reasoning) and Nemotron Diffusion 8B (pst2154, optimized vLLM).

## Summary

- Grok 4.1 Fast (Reasoning) and Nemotron Diffusion 8B (pst2154, optimized vLLM) do not currently share a sourced benchmark row. The mirror therefore compares metadata, pricing, context windows, and each model's separately reported coverage without naming a benchmark winner.

## Model Snapshot

| Property | Grok 4.1 Fast (Reasoning) | Nemotron Diffusion 8B (pst2154, optimized vLLM) |
|----------|----------|----------|
| Creator | xAI | pst2154 |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Non-Reasoning |
| Context | 2M | null |
| Independent public score (not head-to-head) | 46.84 | null |
| Benchmarks Covered | 1 | 1 |
| Pricing (input/output) | N/A | Pricing unavailable / Pricing unavailable |

## Category Breakdown

### Coding

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 27.4 (Estimated · #100/144)
- Nemotron Diffusion 8B (pst2154, optimized vLLM) public-lane score: Coming soon

| Benchmark | Grok 4.1 Fast (Reasoning) | Nemotron Diffusion 8B (pst2154, optimized vLLM) | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 1.20% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 73.2 (Unranked · 2 rankable rows)
- Nemotron Diffusion 8B (pst2154, optimized vLLM) public-lane score: Coming soon

| Benchmark | Grok 4.1 Fast (Reasoning) | Nemotron Diffusion 8B (pst2154, optimized vLLM) | Winner |
|-----------|-----------|-----------|--------|
| JevBench 1.5 | Coming soon | 25.68 | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 54.4 (Unranked · 1 rankable row)
- Nemotron Diffusion 8B (pst2154, optimized vLLM) public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 41.7 (Estimated · #96/170)
- Nemotron Diffusion 8B (pst2154, optimized vLLM) public-lane score: Coming soon

### Instruction Following

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 61.6 (#73/124)
- Nemotron Diffusion 8B (pst2154, optimized vLLM) public-lane score: Coming soon

## FAQ

### Can I compare Grok 4.1 Fast (Reasoning) and Nemotron Diffusion 8B (pst2154, optimized vLLM) on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but sourced benchmark coverage is still incomplete for a fair score-level comparison.

### Why does this page show "coming soon" values?

BenchLM only calls winners when public benchmark coverage is available on both sides of the comparison.

## Related Comparisons

- [Grok 4.1 Fast (Reasoning) vs Grok 4.1 Fast](/compare/grok-4-1-fast-vs-grok-4-1-fast-reasoning)
- [Nemotron Diffusion 8B (pst2154, optimized vLLM) vs Grok 4.1 Fast](/compare/grok-4-1-fast-vs-jevbench-nemotron-diffusion-8b)
- [Grok 4.1 Fast (Reasoning) vs GPT-6 Astra](/compare/gpt-6-astra-vs-grok-4-1-fast-reasoning)
- [Nemotron Diffusion 8B (pst2154, optimized vLLM) vs GPT-6 Astra](/compare/gpt-6-astra-vs-jevbench-nemotron-diffusion-8b)

## Explore More

- [Grok 4.1 Fast (Reasoning) profile](/models/grok-4-1-fast-reasoning)
- [Nemotron Diffusion 8B (pst2154, optimized vLLM) profile](/models/jevbench-nemotron-diffusion-8b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)