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HEAD TO HEAD · UPDATED NOV 6, 2026
Claude Sonnet 5.5 vs Muse Spark Open
Anthropic against Meta, on sourced numbers only. Green marks the higher (or cheaper) value on each row; the text below only calls a lead when the gap is bigger than measurement noise.
| Claude Sonnet 5.5 | Muse Spark Open | |
|---|---|---|
| Arena Elo | 1477 source ↗ | not published |
| GPQA Diamond | 95.6% source ↗ | 89.0% source ↗ |
| $ per 1M in / out | $2 / $10 source ↗ | $1.25 / $4.25 source ↗ |
| Blended $ per 1M (3:1) | $4.00 source ↗ | $2.00 source ↗ |
| Context window | 1M source ↗ | 1M source ↗ |
| Output speed | 155 tok/s source ↗ | 153 tok/s source ↗ |
| Released | Sep 28, 2026 source ↗ | Oct 15, 2026 source ↗ |
| Open weights | No source ↗ | Yes source ↗ |
| Reasoning effort tiers | low · medium · high · xhigh · max (default: high) | not verified (default: not stated) |
| API effort control | output_config={"effort": "low" | "medium" | "high" | "xhigh" | "max"} source ↗ | Not verified: reasoning controls depend on the host source ↗ |
| Additional benchmarks | SWE-bench Pro: 81.3% source ↗ AA Intelligence Index v5.0.1: 55 source ↗ | Size: 816B total, 42B active (MoE) source ↗ Output speed: 153 tok/s, varies by host source ↗ |
| Best for (workload) | Fast (155 tok/s, Artificial Analysis) and strong on science: 95.6% GPQA Diamond at max effort (Epoch AI), above Opus 5.5's 90.6%. source ↗ | Meta's large open-weights model (816B total, 42B active) with a 1M context window; 89.0% GPQA Diamond (Meta). source ↗ |
Arena Elo from the arena.ai text leaderboard as of Oct 27, 2026 source ↗. Speed measured by Artificial Analysis and varies by provider.
Which one should I use?
For high-volume work where cost matters most, Muse Spark Open is about 2.0 times cheaper per token. For hard science and analysis questions, Claude Sonnet 5.5 scores higher on GPQA Diamond (95.6% vs 89.0%). If you need to self-host or fine-tune, only Muse Spark Open has open weights. On release timing, Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP), and Meta is at day 22 of a typical ~14-day gap (PAST TYPICAL GAP).
Key differences from the sourced numbers
- Muse Spark Open is the cheaper option: $2.00 vs $4.00 per 1M tokens at a 3:1 input-to-output mix (about 2.0 times less).
- On GPQA Diamond, graduate-level science questions, Claude Sonnet 5.5 leads 95.6% to 89.0%.
- Claude Sonnet 5.5 pricing note: Same rate across the full 1M context window.
- Muse Spark Open pricing note: Hosted price on OpenRouter (ID meta/muse-spark-open) and Together AI (ID meta-models/Muse-Spark-Open-816B-A42B). Open weights under the Muse Model License.
Frequently asked questions
Is Claude Sonnet 5.5 or Muse Spark Open better?
Muse Spark Open is the cheaper option: $2.00 vs $4.00 per 1M tokens at a 3:1 input-to-output mix (about 2.0 times less). On GPQA Diamond, graduate-level science questions, Claude Sonnet 5.5 leads 95.6% to 89.0%. Claude Sonnet 5.5 pricing note: Same rate across the full 1M context window. Muse Spark Open pricing note: Hosted price on OpenRouter (ID meta/muse-spark-open) and Together AI (ID meta-models/Muse-Spark-Open-816B-A42B). Open weights under the Muse Model License.
Which one should I use: Claude Sonnet 5.5 or Muse Spark Open?
For high-volume work where cost matters most, Muse Spark Open is about 2.0 times cheaper per token. For hard science and analysis questions, Claude Sonnet 5.5 scores higher on GPQA Diamond (95.6% vs 89.0%). If you need to self-host or fine-tune, only Muse Spark Open has open weights. On release timing, Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP), and Meta is at day 22 of a typical ~14-day gap (PAST TYPICAL GAP).
How much does Claude Sonnet 5.5 cost compared with Muse Spark Open?
Claude Sonnet 5.5 lists at $2 / $10 per 1M input/output tokens ($4.00/1M blended at 3:1). Muse Spark Open lists at $1.25 / $4.25 per 1M input/output tokens ($2.00/1M blended at 3:1).
Facts checked Nov 5, 2026 against official sources. Every number links to its source. Spotted an error? Email [email protected].