Model comparison
GPT-5.4 nano vs Grok 4 Fast (Reasoning)
Head-to-head evidence from 13 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.4 nano #25 (Supported); Grok 4 Fast (Reasoning) #76 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.4 nano and Grok 4 Fast (Reasoning) share 13 comparable benchmark results. 0 of 8 categories are comparable. 16 results are unique to GPT-5.4 nano; 0 to Grok 4 Fast (Reasoning).
Updated July 23, 2026- Shared results
- 13
- GPT-5.4 nano only
- 16
- Grok 4 Fast (Reasoning) only
- 0
- Comparable categories
- 0 / 8
Benchmark data for GPT-5.4 nano and Grok 4 Fast (Reasoning) is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 13 shared benchmark results across 6 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
Grok 4 Fast (Reasoning) has the larger context window at 2M, compared with 400K for GPT-5.4 nano.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | GPT-5.4 nano | Δ | Grok 4 Fast (Reasoning) |
|---|---|---|---|
| Agentic | GPT-5.4 nano42.9 | MarginNo overlap | Grok 4 Fast (Reasoning)Not measured |
| Knowledge | GPT-5.4 nano43.8 | MarginNo overlap | Grok 4 Fast (Reasoning)Not measured |
| Math | GPT-5.4 nano21.0 | MarginNo overlap | Grok 4 Fast (Reasoning)Not measured |
| Multimodal | GPT-5.4 nano66.1 | MarginNo overlap | Grok 4 Fast (Reasoning)Not measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.4 nano | Grok 4 Fast (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.4 nano$0.2 input / $1.25 output | Grok 4 Fast (Reasoning)Not available | A complete price comparison is not available. |
| Generation speedtokens per second | GPT-5.4 nano191 tok/s | Grok 4 Fast (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.4 nano3.64 s | Grok 4 Fast (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.4 nano400K | Grok 4 Fast (Reasoning)2M | Grok 4 Fast (Reasoning) lists the larger context window. |
Benchmark Deep Dive
Agentic9 benchmarks
| Benchmark | GPT-5.4 nano | Grok 4 Fast (Reasoning) | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 46.3% | — | Not comparable |
| OSWorld-VerifiedSource | 39% | — | Not comparable |
| MCP AtlasSource | 56.1% | — | Not comparable |
| ToolathlonSource | 35.5% | — | Not comparable |
| τ²-bench resultsSource | 76% | 65.8% | GPT-5.4 nano leads |
| AA Agentic IndexSource | 27.5% | — | Not comparable |
| APEX-Agents-AASource | 24.9% | — | Not comparable |
| GDPval-AASource | 30.0% | — | Not comparable |
| GDPval-AASource | 1100 | — | Not comparable |
Coding3 benchmarks
Reasoning2 benchmarks
Knowledge9 benchmarks
| Benchmark | GPT-5.4 nano | Grok 4 Fast (Reasoning) | Result |
|---|---|---|---|
| GPQASource | 82.8% | — | Not comparable |
| HLESource | 37.7% | — | Not comparable |
| HLE w/o toolsSource | 24.3% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 38.2% | 27.4% | GPT-5.4 nano leads |
| AA-GPQA DiamondSource | 81.7% | 84.7% | Grok 4 Fast (Reasoning) leads |
| AA-HLESource | 26.5% | 17.0% | GPT-5.4 nano leads |
| AA-Omniscience IndexSource | -29.5% | -28.4% | Grok 4 Fast (Reasoning) leads |
| AA-Omniscience AccuracySource | 25.4% | 22.6% | GPT-5.4 nano leads |
| AA-Omniscience Hallucination RateSource | 73.6% | 66.0% | Grok 4 Fast (Reasoning) leads |
Math2 benchmarks
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.4 nano | Grok 4 Fast (Reasoning) | Result |
|---|---|---|---|
| AA-IFBenchSource | 75.9% | 50.5% | GPT-5.4 nano leads |
Frequently Asked Questions (3)
Can I compare GPT-5.4 nano and Grok 4 Fast (Reasoning) on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for GPT-5.4 nano and Grok 4 Fast (Reasoning) today?
GPT-5.4 nano: $0.20 input / $1.25 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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