Model comparison
GPT-5.5 vs Grok Code Fast 1
Head-to-head evidence from 11 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.5 #9 (Estimated); Grok Code Fast 1 #180 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.5 and Grok Code Fast 1 share 11 comparable benchmark results. 1 of 8 categories are comparable. 46 results are unique to GPT-5.5; 1 to Grok Code Fast 1.
Updated July 22, 2026- Shared results
- 11
- GPT-5.5 only
- 46
- Grok Code Fast 1 only
- 1
- Comparable categories
- 1 / 8
Pick GPT-5.5 if you want the stronger benchmark profile. Grok Code Fast 1 only becomes the better choice if coding is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 11 shared benchmark results across 5 evidence categories; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
GPT-5.5 is clearly ahead on the BenchAlign aggregate, 73.51 to 38.64. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $0.20 input / $1.50 output per 1M tokens for Grok Code Fast 1. That is roughly 20.0x on output cost alone. GPT-5.5 is the reasoning model in the pair, while Grok Code Fast 1 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. GPT-5.5 gives you the larger context window at 1M, compared with 256K for Grok Code Fast 1.
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-5.5 | Δ | Grok Code Fast 1 |
|---|---|---|---|
| Coding | GPT-5.558.6 | Margin→ 12.2 | Grok Code Fast 170.8 |
| Agentic | GPT-5.581.6 | MarginNo overlap | Grok Code Fast 1Not measured |
| Reasoning | GPT-5.585.0 | MarginNo overlap | Grok Code Fast 1Not measured |
| Knowledge | GPT-5.557.8 | MarginNo overlap | Grok Code Fast 1Not measured |
| Math | GPT-5.547.6 | MarginNo overlap | Grok Code Fast 1Not measured |
| Multimodal | GPT-5.570.4 | MarginNo overlap | Grok Code Fast 1Not measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.5 | Grok Code Fast 1 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.5$5 input / $30 output | Grok Code Fast 1$0.2 input / $1.5 output | Grok Code Fast 1 has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.5Not available | Grok Code Fast 1172 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.5Not available | Grok Code Fast 12.81 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.51M | Grok Code Fast 1256K | GPT-5.5 lists the larger context window. |
Benchmark Deep Dive
Agentic24 benchmarks
| Benchmark | GPT-5.5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 82% | — | Not comparable |
| CyberGymSource | 81.8% | — | Not comparable |
| BrowseCompSource | 84.4% | — | Not comparable |
| OSWorld-VerifiedSource | 78.7% | — | Not comparable |
| MCP AtlasSource | 75.3% | — | Not comparable |
| ToolathlonSource | 55.6% | — | Not comparable |
| τ²-bench resultsSource | 93.9% | 75.7% | GPT-5.5 leads |
| AA Agentic IndexSource | 44.9% | — | Not comparable |
| APEX-Agents-AASource | 37.7% | — | Not comparable |
| GDPval-AASource | 49.5% | — | Not comparable |
| GDPval-AASource | 1490 | — | Not comparable |
| Gert LabsSource | 72.93% | — | Not comparable |
| ResearchClawBenchSource | 17.0% | — | Not comparable |
| OSWorld 2.0Source | 13.0% | — | Not comparable |
| JobBenchSource | 42.7% | — | Not comparable |
| ExploitGymSource | 13.4% | — | Not comparable |
| AA BriefcaseSource | 1154 | — | Not comparable |
| AA AutomationBenchSource | 42.1% | — | Not comparable |
| AA EnterpriseOps-GymSource | 46.6% | — | Not comparable |
| AA Harvey LABSource | 86.3% | — | Not comparable |
| AA ITBenchSource | 45.8% | — | Not comparable |
| AA Tau3 BankingSource | 31.3% | — | Not comparable |
| terminalBenchHardSource | 60.6% | — | Not comparable |
| aaTerminalBench21Source | 84.3% | — | Not comparable |
CodingGrok Code Fast 1 wins10 benchmarks
| Benchmark | GPT-5.5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| SWE-bench ProSource | 58.6% | — | Not comparable |
| Terminal-Bench 2.0Source | 82.0% | — | Not comparable |
| Vibe Code BenchSource | 69.85% | — | Not comparable |
| React Native EvalsSource | 84.7% | — | Not comparable |
| cursorBench31Source | 59.2% | — | Not comparable |
| cursorBench32Source | 58.4% | — | Not comparable |
| AA Coding IndexSource | 74.9% | — | Not comparable |
| AA-SciCodeSource | 56.1% | 36.2% | GPT-5.5 leads |
| FrontierCode 1.1 MainSource | 43.0% | — | Not comparable |
| SWE-bench VerifiedSource | — | 70.8% | Not comparable |
Reasoning5 benchmarks
Knowledge10 benchmarks
| Benchmark | GPT-5.5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| GPQASource | 93.6% | — | Not comparable |
| GPQA-DSource | 93.6% | — | Not comparable |
| HLESource | 52.2% | — | Not comparable |
| HLE w/o toolsSource | 41.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 54.8% | 21.6% | GPT-5.5 leads |
| AA-GPQA DiamondSource | 93.5% | 72.7% | GPT-5.5 leads |
| AA-HLESource | 44.3% | 7.5% | GPT-5.5 leads |
| AA-Omniscience IndexSource | 20.1% | -36.0% | GPT-5.5 leads |
| AA-Omniscience AccuracySource | 56.9% | 23.8% | GPT-5.5 leads |
| AA-Omniscience Hallucination RateSource | 85.5% | 78.5% | Grok Code Fast 1 leads |
Math3 benchmarks
Multimodal5 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| AA-IFBenchSource | 75.9% | 41.4% | GPT-5.5 leads |
Frequently Asked Questions (2)
Which is better, GPT-5.5 or Grok Code Fast 1?
GPT-5.5 is ahead on BenchLM's BenchAlign leaderboard, 73.51 to 38.64.
Which is better for coding, GPT-5.5 or Grok Code Fast 1?
Grok Code Fast 1 has the edge for coding in this comparison, averaging 70.8 versus 58.6. Inside this category, AA-SciCode is the benchmark that creates the most daylight between them.
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