Model comparison
Claude Sonnet 4.5 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: Claude Sonnet 4.5 estimated; LFM2.5-8B-A1B estimated. Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Sonnet 4.5 and LFM2.5-8B-A1B share 1 comparable benchmark result. 1 of 8 categories are comparable. 11 results are unique to Claude Sonnet 4.5; 17 to LFM2.5-8B-A1B.
Updated July 16, 2026- Shared results
- 1
- Claude Sonnet 4.5 only
- 11
- LFM2.5-8B-A1B only
- 17
- Comparable categories
- 1 / 8
Pick Claude Sonnet 4.5 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
Claude Sonnet 4.5 is clearly ahead on the provisional aggregate, 59 to 37. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 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. LFM2.5-8B-A1B is the reasoning model in the pair, while Claude Sonnet 4.5 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. Claude Sonnet 4.5 gives you the larger context window at 200K, 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 | Claude Sonnet 4.5 | Δ | LFM2.5-8B-A1B |
|---|---|---|---|
| Math | Claude Sonnet 4.511.2 | Margin→ 38.8 | LFM2.5-8B-A1B50.0 |
| Agentic | Claude Sonnet 4.555.4 | MarginNo overlap | LFM2.5-8B-A1BNot measured |
| Coding | Claude Sonnet 4.577.2 | MarginNo overlap | LFM2.5-8B-A1BNot measured |
| Reasoning | Claude Sonnet 4.513.6 | MarginNo overlap | LFM2.5-8B-A1BNot measured |
| Knowledge | Claude Sonnet 4.583.4 | MarginNo overlap | LFM2.5-8B-A1BNot measured |
| Inst. Following | Claude Sonnet 4.5Not 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 | Claude Sonnet 4.5 | LFM2.5-8B-A1B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Sonnet 4.5$3 input / $15 output | LFM2.5-8B-A1B$0 input / $0 output | LFM2.5-8B-A1B has the lower combined listed price. |
| Generation speedtokens per second | Claude Sonnet 4.5Not available | LFM2.5-8B-A1BNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Sonnet 4.5Not available | LFM2.5-8B-A1BNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Sonnet 4.5200K | LFM2.5-8B-A1B128K | Claude Sonnet 4.5 lists the larger context window. |
Benchmark Deep Dive
Agentic7 benchmarks
| Benchmark | Claude Sonnet 4.5 | LFM2.5-8B-A1B | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 50% | — | Not comparable |
| OSWorld-VerifiedSource | 61.4% | — | Not comparable |
| VITA-BenchSource | 17.0% | — | Not comparable |
| Gert LabsSource | 48.51% | — | Not comparable |
| JobBenchSource | 27.7% | — | Not comparable |
| BFCL v4Source | — | 49.7% | Not comparable |
| τ²-bench resultsSource | — | 16.1% | Not comparable |
Coding3 benchmarks
Reasoning3 benchmarks
Knowledge7 benchmarks
| Benchmark | Claude Sonnet 4.5 | LFM2.5-8B-A1B | Result |
|---|---|---|---|
| GPQASource | 83.4% | — | 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 wins5 benchmarks
Multimodal1 benchmarks
| Benchmark | Claude Sonnet 4.5 | LFM2.5-8B-A1B | Result |
|---|---|---|---|
| Design Arena WebsiteSource | 1224 | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude Sonnet 4.5 or LFM2.5-8B-A1B?
Claude Sonnet 4.5 is ahead on BenchLM's provisional leaderboard, 59 to 37.
Which is better for math, Claude Sonnet 4.5 or LFM2.5-8B-A1B?
LFM2.5-8B-A1B has the edge for math in this comparison, averaging 50 versus 11.2. Inside this category, AIME 2025 is the benchmark that creates the most daylight between them.
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