MModelspectraIndependent AI Model Intelligence
Head-to-head · Updated 2026-09-08
Model Comparison · Head to Head

GPT-5.6 Terra vs Muse Spark 1.1

GPT-5.6 Terra wins on Overall, Coding; Muse Spark 1.1 wins on Multimodal. Every numeric field is compared below, with a worked monthly-cost example and a pick rule for each use case.

VendorOpenAI / Meta
Data fields15+ dimensions
Updated2026-09-08
Read~9 min
01

Verdict at a glance

Bottom line: Choose GPT-5.6 Terra when coding depth, long-context reliability matter most; choose Muse Spark 1.1 when lower cost, fine-tuning/ecosystem is the priority.

Choose GPT-5.6 Terra if you…

  • OpenAI quality
  • Halved price
  • Rich ecosystem
  • Best for: Value, General tasks, OpenAI ecosystem

Choose Muse Spark 1.1 if you…

  • Completely free open weights
  • By Meta
  • Self-hostable
  • Multimodal
  • Best for: Open research, Local deployment, Experimental
02

Head-to-head aggregate scores

Scores are 0–100, aggregated from public benchmark information and independently weighted across three leaderboards. Rank is out of 22 tracked models.

GPT-5.6 Terra Higher overall
OpenAI · #21 overall
Overall62
Coding70
Multimodal69
VS
Muse Spark 1.1
Meta · #22 overall
Overall61
Coding59
Multimodal75

Aggregated from public sources and independently weighted; methodology on the Terms page. Scores within 3 points are treated as statistically tied.

03

Specs & pricing — every field side by side

List API prices in USD per 1M tokens. The highlighted cell is the stronger value/capability on that row.

DimensionGPT-5.6 TerraMuse Spark 1.1Verdict
VendorOpenAI (US)Meta (US)Different vendors
Released2026.072026.08Muse Spark 1.1 is newer
Overall (rank)62 · #2161 · #22GPT-5.6 Terra +1
Coding70 · #1259 · #21GPT-5.6 Terra +11
Multimodal69 · #1975 · #15Muse Spark 1.1 +6
Context window1.05M256KGPT-5.6 Terra larger
Max output128K64KMuse Spark 1.1 longer
Effective-context8880GPT-5.6 Terra more reliable
Input $/1M$2.5FreeMuse Spark 1.1 cheaper
Output $/1M$15FreeMuse Spark 1.1 cheaper
Cache discount50% offnoneGPT-5.6 Terra deeper
Speed~60 tok/sHardware-dependentGPT-5.6 Terra faster
TTFT0.5sHardware-dependentGPT-5.6 Terra snappier
Function calling9065GPT-5.6 Terra ahead
Refusal rate~13%~4%Muse Spark 1.1 less restrictive
English8878GPT-5.6 Terra
Chinese7260GPT-5.6 Terra
Modalitiestext, imagetext, imageSame
Open weightsNoYesMuse Spark 1.1 is open
Fine-tuningNoYes
Free tierNo free APIFully free (model weights)
SOC2 / no-trainyes / yesno / yes
Private deploymentNoYesMuse Spark 1.1

Fields drawn from vendor public documentation and the Modelspectra 22-model dataset; speed varies with network, concurrency and prompt length. Verify current pricing before purchase.

04

Dimension-by-dimension analysis

Reasoning & overall intelligence

GPT-5.6 Terra leads the overall aggregate by 1 points (62 vs 61). That is a meaningful, not marginal, edge on hard, multi-step reasoning, while Muse Spark 1.1 remains a strong generalist that is not out of its depth on routine work.

Agentic coding

This is a clear gap: GPT-5.6 Terra scores 70 against 59. On multi-file edits, SWE-style tickets and long-horizon agent loops GPT-5.6 Terra needs fewer correction turns; Muse Spark 1.1 is still competent for scripts and assisted completion but trails as task complexity rises.

Multimodal

Muse Spark 1.1 leads multimodal 75 vs 69. Neither emits native video, so the comparison is about parsing images and documents, not generation.

Speed & latency

Muse Spark 1.1 is self-hosted, so its speed depends on your hardware; against a managed API like GPT-5.6 Terra (~60 tok/s, 0.5s TTFT) compare on your own infrastructure before assuming latency.

Context: window vs usable recall

Nominal windows are 1.05M for GPT-5.6 Terra and 256K for Muse Spark 1.1. Effective-context scores point the same way as window size — GPT-5.6 Terra is ahead on usable recall (88 vs 80), so prefer it for long-document work where details cannot be missed.

Price & total cost

Muse Spark 1.1 is free open weights (you pay only for the infrastructure you run it on), while GPT-5.6 Terra is a paid API at $2.5/$15 per 1M tokens. The real comparison is total cost of ownership — GPU/ops against a managed bill — not list price alone.

Chinese vs English

English: GPT-5.6 Terra 88 vs Muse Spark 1.1 78. Chinese: 72 vs 60. Both are US-based models; for Chinese-first workloads also compare domestic models on the leaderboard.

Tool use & ecosystem

Function-calling score: GPT-5.6 Terra 90 vs Muse Spark 1.1 65, so GPT-5.6 Terra has the edge on structured tool use. Fine-tuning is available from Muse Spark 1.1. Factor in existing SDK/plugin familiarity — switching cost often outweighs a few-point tool-use gap.

05

Cost worked example — same workload, real token math

Assume a production workload of 100M input + 30M output tokens per month, with 90% of input tokens served from cache. Figures use public list prices.

Cost note: one of these models is free open weights, so a per-token monthly bill does not apply — budget instead for GPU and operations. The paid API counterpart works out to roughly $700/month at list for this workload.

Illustrative model; your input/output mix and cache-hit ratio change the result. Prices are list rates before any enterprise agreement.

06

Decision tree

IF the workload is agentic or multi-file coding and a wrong first pass is expensive  →  choose GPT-5.6 Terra (coding 70 vs 59).
IF you serve real-time users and latency is a product KPI  →  choose GPT-5.6 Terra (~60 tok/s, 0.5s TTFT).
IF you need free, self-hostable weights and can run your own GPU/ops  →  choose Muse Spark 1.1 (free open weights).
IF long-document recall has to be near-perfect  →  choose GPT-5.6 Terra (effective context 88 vs 80).
07

Frequently asked questions

Does GPT-5.6 Terra's higher refusal rate matter in production?
GPT-5.6 Terra refuses about 13% of prompts versus 4% for Muse Spark 1.1. In unattended pipelines that means more retries, fallbacks and manual review, raising effective cost and latency even when the token price is lower.
Does the bigger context window actually matter?
Nominal windows are GPT-5.6 Terra (1.05M) and Muse Spark 1.1 (256K), but usable recall follows the effective-context score (88 vs 80). Prefer the higher effective-context model for long-document work where nothing can be missed.
Can I self-host either model?
Muse Spark 1.1 ships open weights and can be self-hosted (GPU permitting) for data control; GPT-5.6 Terra is a closed managed API with no self-hosting. Choose open weights when residency or cost-at-scale dominates, managed API for convenience.
Which one supports fine-tuning?
Muse Spark 1.1 supports fine-tuning; GPT-5.6 Terra does not at this tier. If you plan to adapt the model to a narrow domain, that is a concrete differentiator.
What is the single-line recommendation?
Choose GPT-5.6 Terra for Value, General tasks; choose Muse Spark 1.1 for Open research, Local deployment.
How quickly do these rankings change?
Modelspectra refreshes the aggregate as new public benchmarks and prices appear. Treat scores within 3 points as a tie and re-check before a committed purchase.