Model comparison
GPT-5.5 Pro vs LFM2.5-8B-A1B
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
BenchAlign evidence: GPT-5.5 Pro estimated; LFM2.5-8B-A1B estimated. Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.5 Pro and LFM2.5-8B-A1B share 1 comparable benchmark result. 1 of 8 categories are comparable. 6 results are unique to GPT-5.5 Pro; 17 to LFM2.5-8B-A1B.
Updated July 16, 2026- Shared results
- 1
- GPT-5.5 Pro only
- 6
- LFM2.5-8B-A1B only
- 17
- Comparable categories
- 1 / 8
Pick GPT-5.5 Pro if you want the stronger benchmark profile. LFM2.5-8B-A1B only becomes the better choice if mathematics is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 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 Pro is clearly ahead on the provisional aggregate, 75 to 37. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for LFM2.5-8B-A1B. That is roughly Infinityx on output cost alone. GPT-5.5 Pro gives you the larger context window at 1M, compared with 128K for LFM2.5-8B-A1B.
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 Pro | Δ | LFM2.5-8B-A1B |
|---|---|---|---|
| Math | GPT-5.5 Pro48.1 | Margin→ 1.9 | LFM2.5-8B-A1B50.0 |
| Agentic | GPT-5.5 Pro90.1 | MarginNo overlap | LFM2.5-8B-A1BNot measured |
| Knowledge | GPT-5.5 Pro57.2 | MarginNo overlap | LFM2.5-8B-A1BNot measured |
| Inst. Following | GPT-5.5 ProNot measured | MarginNo overlap | LFM2.5-8B-A1B68.8 |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.5 Pro | LFM2.5-8B-A1B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.5 Pro$30 input / $180 output | LFM2.5-8B-A1B$0 input / $0 output | LFM2.5-8B-A1B has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.5 ProNot available | LFM2.5-8B-A1BNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.5 ProNot available | LFM2.5-8B-A1BNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.5 Pro1M | LFM2.5-8B-A1B128K | GPT-5.5 Pro lists the larger context window. |
Benchmark Deep Dive
Agentic3 benchmarks
Coding2 benchmarks
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | GPT-5.5 Pro | LFM2.5-8B-A1B | Result |
|---|---|---|---|
| HLESource | 57.2% | — | Not comparable |
| HLE w/o toolsSource | 43.1% | — | Not comparable |
| AA-GPQA DiamondSource | — | 51.3% | Not comparable |
| AA-HLESource | — | 6.9% | Not comparable |
| AA-Omniscience IndexSource | — | -33.3% | Not comparable |
| AA-Omniscience AccuracySource | — | 9.4% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 47.0% | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 8.3% | Not comparable |
MathLFM2.5-8B-A1B wins6 benchmarks
| Benchmark | GPT-5.5 Pro | LFM2.5-8B-A1B | Result |
|---|---|---|---|
| FrontierMath (legacy)Source | 52.4% | — | Not comparable |
| FrontierMath v2 (Tiers 1-3)Source | 51.000% | — | Not comparable |
| FrontierMath v2 (Tier 4)Source | 39.600% | — | Not comparable |
| MATH-500Source | — | 88.8% | Not comparable |
| AIME 2025Source | — | 42.5% | Not comparable |
| AIME26Source | — | 50.0% | Not comparable |
Frequently Asked Questions (2)
Which is better, GPT-5.5 Pro or LFM2.5-8B-A1B?
GPT-5.5 Pro is ahead on BenchLM's provisional leaderboard, 75 to 37.
Which is better for math, GPT-5.5 Pro or LFM2.5-8B-A1B?
LFM2.5-8B-A1B has the edge for math in this comparison, averaging 50 versus 48.1. GPT-5.5 Pro stays close enough that the answer can still flip depending on your workload.
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