Hermes 4 405B vs Sonar
Updated October 21, 2026. 1 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Neither model has a coding score yet, so the two cannot be ranked on coding.
Hermes 4 405B has the edge where the context window is larger, 131K against 127K tokens, and where the benchmark that matters is AA Intelligence Index, where it leads.
- Shared results
- 1
- Hermes 4 405B only
- 0
- Sonar only
- 4
- Like-for-like categories
- 1 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
Sonar
Sonar leads, 7.7 against 7.5.
Same board, both measured
Long documents
Listed context window
Hermes 4 405B
Hermes 4 405B takes 131K tokens against 127K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Sonar
Hermes 4 405B $0.0025, Sonar $0.0015 per turn.
List prices
At a glance
- Coding index
- Hermes 4 405B not benchmarked, Sonar not benchmarked.
- Widest category
- Intelligence, 0.2 points apart on average over 1 shared benchmark.
- Widest single gap
- AA Intelligence Index: Hermes 4 405B 7.5 against Sonar 7.7, 0.2 points apart on a 0 to 100 scale.
- Output price
- Hermes 4 405B $3.00 against Sonar $1.00 per million output tokens, 3.0x apart.
- Context window
- Hermes 4 405B takes 131K tokens, Sonar 127K.
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 | Hermes 4 405B | Bars | Sonar | Ties |
|---|---|---|---|---|
| Intelligence | 0 | 1 | ||
| All shared boards | 0 | 1 |
CodingDirectional onlySix of these boards feed the Vibe Coding Index1 board, none shared
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| LiveCodeBench (Artificial Analysis run) | Not measured | 29.5% | Only Sonar measured |
| Neither model has a result on the other 37 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| AA Intelligence Index | 7.5 | 7.7 | Sonar |
| Neither model has a result on the other 1 board here | |||
Agentic workNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| Neither model has a result on 39 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | Not measured | 47.1% | Only Sonar measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 4.9% | Only Sonar measured |
| Neither model has a result on the other 19 boards here | |||
MathNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| Neither model has a result on 13 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| MMLU Pro (Artificial Analysis run) | Not measured | 68.9% | Only Sonar measured |
| Neither model has a result on the other 16 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | Sonar | Leader |
|---|---|---|---|
| Neither model has a result on 46 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | Sonar | 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
Sonar costs less
Repository review
50K input + 3K output tokens
Sonar costs less
Agent loop
200K input + 10K output tokens
Sonar 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 | Nous Hermes 4 405B | Perplexity Sonar |
|---|---|---|
| Maker | Nous Research | Perplexity |
| Weights | Open weights | No public weights listed |
| Released | August 26, 2025 | January 27, 2025 |
| Context window | 131K | 127K |
| Input $/Mtok | $1.00 | $1.00 |
| Output $/Mtok | $3.00 | $1.00 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Hermes 4 405B better than Sonar for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Hermes 4 405B has the edge where the context window is larger, 131K against 127K tokens, and where the benchmark that matters is AA Intelligence Index, where it leads.
Which is cheaper, Hermes 4 405B or Sonar?
Hermes 4 405B costs $1.00 per million input tokens and $3.00 per million output tokens; Sonar costs $1.00 and $1.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Hermes 4 405B or Sonar?
Hermes 4 405B, with 131K tokens against 127K.
How many benchmarks is the Hermes 4 405B vs Sonar comparison based on?
1 benchmarks have a result for both models as of October 21, 2026. Hermes 4 405B's coding index rests on 0 independent benchmarks and Sonar's on 0. Where only one model has a result, the page says so instead of naming a winner.