Ember-1 vs GPT-5.4 Nano
Ember-1 leads GPT-5.4 Nano on coding, 52.6 to 44.8 on the Vibe Coding Index, and GPT-5.4 Nano costs 12.0x less per output token ($1.25 vs $15.00 per million). Updated October 22, 2026; 6 benchmarks have a result for both.
Ember-1 or GPT-5.4 Nano: which to pick
Pick Ember-1 for coding: it scores 52.6 on the Vibe Coding Index against 44.8 for GPT-5.4 Nano.
Pick GPT-5.4 Nano for output tokens 12.0x cheaper ($1.25 vs $15.00 per million).
- Shared results
- 6
- Ember-1 only
- 8
- GPT-5.4 Nano only
- 79
- Like-for-like categories
- 2 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
Ember-1
Ember-1 scores 52.6 against 44.8.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
No call
Only GPT-5.4 Nano has a AA Intelligence Index result, 20.7.
Directional only
Agentic work
AA Agentic Index
No call
Only GPT-5.4 Nano has a AA Agentic Index result, 16.0.
Directional only
Reasoning
GPQA Diamond
No call
Only GPT-5.4 Nano has a GPQA Diamond result, 77.5%.
Directional only
Math
AIME
No call
Only GPT-5.4 Nano has a AIME result, 88.8%.
Directional only
Knowledge
MMLU Pro
No call
Only GPT-5.4 Nano has a MMLU Pro result, 77.2%.
Directional only
Long documents
Listed context window
Ember-1
Ember-1 takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5.4 Nano
Ember-1 $0.011, GPT-5.4 Nano $0.0008 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.4 Nano has the number, $0.14.
Directional only
At a glance
- Coding index
- Ember-1 52.6 from 2 benchmarks, GPT-5.4 Nano 44.8 from 2 benchmarks.
- Widest category
- Coding, 37.9 points apart on average over 2 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): Ember-1 83.9% against GPT-5.4 Nano 26.1%, 57.8 points apart on a 0 to 100 scale.
- Output price
- Ember-1 $15.00 against GPT-5.4 Nano $1.25 per million output tokens, 12.0x apart.
- Context window
- Ember-1 takes 1.05M tokens, GPT-5.4 Nano 400K.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Ember-1 | Bars | GPT-5.4 Nano | Ties |
|---|---|---|---|---|
| Coding | 2 | 0 | ||
| Agentic work | 4 | 0 | ||
| All shared boards | 6 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index20
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| AA Coding Index | Not measured | 56.1 | Only GPT-5.4 Nano measured |
| LiveCodeBench (Vals AI) | Not measured | 84.0% | Only GPT-5.4 Nano measured |
| SWE-bench Verified (Vals AI) | Not measured | 69.8% | Only GPT-5.4 Nano measured |
| Terminal-Bench 4 (Vals AI) | 20.7% | Not measured | Only Ember-1 measured |
| Vibe Code Bench (Vals AI) | 83.9% | 26.1% | Ember-1 |
| Code migration (Vals AI) | 32.5% | 14.5% | Ember-1 |
| IOI (Vals AI) | 46.3% | Not measured | Only Ember-1 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 41.6% | Only GPT-5.4 Nano measured |
| CyberBench (Vals AI) | 69.5% | Not measured | Only Ember-1 measured |
| SciCode | Not measured | 47.2% | Only GPT-5.4 Nano measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 42.4% | Only GPT-5.4 Nano measured |
| WeirdML | Not measured | 49.2% | Only GPT-5.4 Nano measured |
| ALE-Bench | Not measured | 1004.5 | Only GPT-5.4 Nano measured |
| LMArena Text: coding | Not measured | 1404 | Only GPT-5.4 Nano measured |
| LMArena Text: software and IT | Not measured | 1402 | Only GPT-5.4 Nano measured |
| Neither model has a result on the other 24 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 20.7 | Only GPT-5.4 Nano measured |
| Epoch Capabilities Index | Not measured | 146.0 | Only GPT-5.4 Nano measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 16.0 | Only GPT-5.4 Nano measured |
| Finance Agent (Vals AI) | 51.8% | 38.2% | Ember-1 |
| Tax Agent Bench (Vals AI) | 31.1% | 5.0% | Ember-1 |
| Legal Research Bench (Vals AI) | 44.7% | 6.3% | Ember-1 |
| Excel Modeling Benchmark (Vals AI) | 63.4% | 44.8% | Ember-1 |
| BioMysteryBench (Vals AI) | 67.0% | Not measured | Only Ember-1 measured |
| Terminal-Bench-Science (Vals AI) | 5.7% | Not measured | Only Ember-1 measured |
| Vals Science Index | 31.8% | Not measured | Only Ember-1 measured |
| τ²-Bench Telecom | Not measured | 76.0% | Only GPT-5.4 Nano measured |
| Neither model has a result on the other 32 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index16 boards, none shared
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 77.5% | Only GPT-5.4 Nano measured |
| MysteryMechanism (Vals AI) | 22.5% | Not measured | Only Ember-1 measured |
| MMMU Pro (Vals AI) | Not measured | 73.6% | Only GPT-5.4 Nano measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 81.7% | Only GPT-5.4 Nano measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 28.3% | Only GPT-5.4 Nano measured |
| GPQA Diamond (Epoch AI run) | Not measured | 78.5% | Only GPT-5.4 Nano measured |
| ARC-AGI | Not measured | 51.5% | Only GPT-5.4 Nano measured |
| ARC-AGI-2 | Not measured | 5.7% | Only GPT-5.4 Nano measured |
| Chess puzzles | Not measured | 45.0% | Only GPT-5.4 Nano measured |
| Mystery game puzzles | Not measured | 9.0% | Only GPT-5.4 Nano measured |
| LMArena Text: hard prompts | Not measured | 1381 | Only GPT-5.4 Nano measured |
| LMArena Text: expert | Not measured | 1396 | Only GPT-5.4 Nano measured |
| LMArena Text: hard prompts in English | Not measured | 1387 | Only GPT-5.4 Nano measured |
| LMArena Vision: diagrams | Not measured | 1210 | Only GPT-5.4 Nano measured |
| LMArena Vision: homework | Not measured | 1225 | Only GPT-5.4 Nano measured |
| Kagi LLM Benchmark | Not measured | 39.7% | Only GPT-5.4 Nano measured |
| Neither model has a result on the other 6 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| AIME | Not measured | 88.8% | Only GPT-5.4 Nano measured |
| OTIS Mock AIME | Not measured | 87.8% | Only GPT-5.4 Nano measured |
| FrontierMath, tiers 1 to 3 | Not measured | 44.9% | Only GPT-5.4 Nano measured |
| FrontierMath, tier 4 | Not measured | 12.2% | Only GPT-5.4 Nano measured |
| ProofBench | Not measured | 5.0% | Only GPT-5.4 Nano measured |
| LMArena Text: math | Not measured | 1405 | Only GPT-5.4 Nano measured |
| LMArena Text: mathematical work | Not measured | 1409 | Only GPT-5.4 Nano measured |
| Neither model has a result on the other 6 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 77.2% | Only GPT-5.4 Nano measured |
| LegalBench (Vals AI) | Not measured | 77.9% | Only GPT-5.4 Nano measured |
| CaseLaw (Vals AI) | Not measured | 51.9% | Only GPT-5.4 Nano measured |
| CorpFin (Vals AI) | Not measured | 61.2% | Only GPT-5.4 Nano measured |
| TaxEval (Vals AI) | Not measured | 67.4% | Only GPT-5.4 Nano measured |
| MortgageTax (Vals AI) | Not measured | 59.1% | Only GPT-5.4 Nano measured |
| MedCode (Vals AI) | Not measured | 41.0% | Only GPT-5.4 Nano measured |
| SimpleQA Verified | Not measured | 11.7% | Only GPT-5.4 Nano measured |
| LMArena Text: science | Not measured | 1374 | Only GPT-5.4 Nano measured |
| LMArena Text: medicine and healthcare | Not measured | 1369 | Only GPT-5.4 Nano measured |
| LMArena Text: legal and government | Not measured | 1368 | Only GPT-5.4 Nano measured |
| LMArena Text: business and finance | Not measured | 1366 | Only GPT-5.4 Nano measured |
| Neither model has a result on the other 6 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index32 boards, none shared
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| Public Benefits Bench (Vals AI) | 66.2% | Not measured | Only Ember-1 measured |
| SAGE (Vals AI) | Not measured | 38.1% | Only GPT-5.4 Nano measured |
| MedScribe (Vals AI) | Not measured | 77.1% | Only GPT-5.4 Nano measured |
| Vals Multimodal Index | Not measured | 47.6% | Only GPT-5.4 Nano measured |
| IFBench | Not measured | 75.9% | Only GPT-5.4 Nano measured |
| Long context reasoning (AA-LCR) | Not measured | 76.7% | Only GPT-5.4 Nano measured |
| DTBench | Not measured | 80.3% | Only GPT-5.4 Nano measured |
| LMCA | Not measured | 36.9% | Only GPT-5.4 Nano measured |
| LMArena Text | Not measured | 1372 | Only GPT-5.4 Nano measured |
| LMArena Text: instruction following | Not measured | 1362 | Only GPT-5.4 Nano measured |
| LMArena Text: creative writing | Not measured | 1315 | Only GPT-5.4 Nano measured |
| LMArena Vision | Not measured | 1196 | Only GPT-5.4 Nano measured |
| LMArena Text: English | Not measured | 1381 | Only GPT-5.4 Nano measured |
| LMArena Text: non-English | Not measured | 1359 | Only GPT-5.4 Nano measured |
| LMArena Text: Chinese | Not measured | 1391 | Only GPT-5.4 Nano measured |
| LMArena Text: German | Not measured | 1368 | Only GPT-5.4 Nano measured |
| LMArena Text: Japanese | Not measured | 1343 | Only GPT-5.4 Nano measured |
| LMArena Text: Korean | Not measured | 1321 | Only GPT-5.4 Nano measured |
| LMArena Text: French | Not measured | 1395 | Only GPT-5.4 Nano measured |
| LMArena Text: Spanish | Not measured | 1371 | Only GPT-5.4 Nano measured |
| LMArena Text: Russian | Not measured | 1363 | Only GPT-5.4 Nano measured |
| LMArena Text: Polish | Not measured | 1366 | Only GPT-5.4 Nano measured |
| LMArena Text: multi-turn | Not measured | 1382 | Only GPT-5.4 Nano measured |
| LMArena Text: longer queries | Not measured | 1365 | Only GPT-5.4 Nano measured |
| LMArena Text: writing and language | Not measured | 1338 | Only GPT-5.4 Nano measured |
| LMArena Text: entertainment and media | Not measured | 1325 | Only GPT-5.4 Nano measured |
| LMArena Vision: English | Not measured | 1202 | Only GPT-5.4 Nano measured |
| LMArena Vision: Chinese | Not measured | 1232 | Only GPT-5.4 Nano measured |
| LMArena Vision: reading text | Not measured | 1204 | Only GPT-5.4 Nano measured |
| LMArena Vision: humor | Not measured | 1161 | Only GPT-5.4 Nano measured |
| LMArena Vision: recognizing things | Not measured | 1141 | Only GPT-5.4 Nano measured |
| LMArena Vision: creative writing | Not measured | 1159 | Only GPT-5.4 Nano measured |
| Neither model has a result on the other 14 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Ember-1 | GPT-5.4 Nano | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
GPT-5.4 Nano costs less
Repository review
50K input + 3K output tokens
GPT-5.4 Nano costs less
Agent loop
200K input + 10K output tokens
GPT-5.4 Nano costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Fireworks Ember-1 | OpenAI GPT-5.4 Nano |
|---|---|---|
| Maker | Fireworks | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 24, 2026 | March 17, 2026 |
| Context window | 1.05M | 400K |
| Input $/Mtok | $3.00 | $0.20 |
| Output $/Mtok | $15.00 | $1.25 |
| Coding index | 52.6 | 44.8 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | Not computable | $0.14 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Ember-1 better than GPT-5.4 Nano for coding?
Pick Ember-1 for coding: it scores 52.6 on the Vibe Coding Index against 44.8 for GPT-5.4 Nano. Pick GPT-5.4 Nano for output tokens 12.0x cheaper ($1.25 vs $15.00 per million).
Which is cheaper, Ember-1 or GPT-5.4 Nano?
Ember-1 costs $3.00 per million input tokens and $15.00 per million output tokens; GPT-5.4 Nano costs $0.20 and $1.25. Cost per solved task is known for GPT-5.4 Nano only.
Which has the bigger context window, Ember-1 or GPT-5.4 Nano?
Ember-1, with 1.05M tokens against 400K.
How many benchmarks is the Ember-1 vs GPT-5.4 Nano comparison based on?
6 benchmarks have a result for both models as of October 22, 2026. Ember-1's coding index rests on 2 independent benchmarks and GPT-5.4 Nano's on 2. Where only one model has a result, the page says so instead of naming a winner.