vs
0:5
overall capability wins (0 ties across 5 scored). K2 Horizon 375B A23B leads overall.
- Reasoning0:3
- Specs0:2
Verdict
K2 Horizon 375B A23B edges reasoning & knowledge; K2 Horizon 375B A23B offers ~8.0x larger context (524K vs 66K).
- K2 Horizon 375B A23B edges reasoning & knowledge
- K2 Horizon 375B A23B offers ~8.0x larger context (524K vs 66K)
Cost for 1M in + 250K out
Illustrative chat workload at primary-provider list prices.
- Apertus 8B Instruct
- $0.15
- K2 Horizon 375B A23B
- -
Price per 1M tokens
Full comparison
Organization
Swiss AI Initiative
MBZUAI Institute of Foundation Models
Family
Other
Other
License
Apache 2.0
Apache 2.0
Open weights
Yes
Yes
Release
Sep 2, 2025
Sep 3, 2026
Knowledge cutoff
-
-
API / provider
Public AI
No primary API price listed
Modalities
text → text
text → text
Specs
Context window
66K
524K
Max output
-
-
Parameters
8B
375B (23B act.)
Pricing
Input $/1M
$0.10
—
Output $/1M
$0.20
—
Blended $/1M (3∶1)
$0.13
-
Speed
tok/s
-
-
TTFT (s)
-
-
Reasoning
MMLU-Pro
—
—
GPQA Diamond
25.6
87.3
Humanity's Last Exam
5.0
32.0
AIME 2025
—
—
MATH-500
—
—
Humanity's Last Exam (with tools)
—
—
AA-Omniscience Accuracy
9.7
18.2
AA-LCR v1.1
—
80.0
CritPt
—
4.6
MMMU-Pro
—
—
IFBench
22.4
—
Chartography
—
—
Chartography (With Tools)
—
—
Coding
SWE-bench Verified
—
—
SWE-bench Pro
—
—
SWE-bench Multilingual
—
—
LiveCodeBench
—
—
Terminal-Bench 2.1
—
71.9
Aider Polyglot
—
—
Terminal-Bench 3
—
—
BigCodeBench
—
—
SciCode
—
42.9
CursorBench
—
—
SWE-Rebench
—
—
NL2Repo-Bench
—
—
DeepSWE
—
—
WebDev Arena
—
—
Terminal-Bench 4.0
—
—
CursorBench 4.0
—
—
FrontierCode v1.1 (Main)
—
—
Arena
LMArena Elo
—
—
| Metric | Apertus 8B Instruct | K2 Horizon 375B A23B | Delta |
|---|---|---|---|
| Identity | |||
| Organization | Swiss AI Initiative | MBZUAI Institute of Foundation Models | — |
| Family | Other | Other | — |
| License | Apache 2.0 | Apache 2.0 | — |
| Open weights | Yes | Yes | — |
| Release | Sep 2, 2025 | Sep 3, 2026 | — |
| Knowledge cutoff | - | - | — |
| API / provider | Public AI | No primary API price listed | — |
| Modalities | text → text | text → text | — |
| Specs | |||
| Context window | 66K | 524K | B +459K |
| Max output | - | - | — |
| Parameters | 8B | 375B (23B act.) | B +367 |
| Pricing | |||
| Input $/1M | $0.10 | — | — |
| Output $/1M | $0.20 | — | — |
| Blended $/1M (3∶1) | $0.13 | - | — |
| Speed | |||
| tok/s | - | - | — |
| TTFT (s) | - | - | — |
| Reasoning | |||
| MMLU-Pro | — | — | — |
| GPQA Diamond | 25.6 | 87.3 | B +61.7 pts |
| Humanity's Last Exam | 5.0 | 32.0 | B +27.0 pts |
| AIME 2025 | — | — | — |
| MATH-500 | — | — | — |
| Humanity's Last Exam (with tools) | — | — | — |
| AA-Omniscience Accuracy | 9.7 | 18.2 | B +8.5 pts |
| AA-LCR v1.1 | — | 80.0 | — |
| CritPt | — | 4.6 | — |
| MMMU-Pro | — | — | — |
| IFBench | 22.4 | — | — |
| Chartography | — | — | — |
| Chartography (With Tools) | — | — | — |
| Coding | |||
| SWE-bench Verified | — | — | — |
| SWE-bench Pro | — | — | — |
| SWE-bench Multilingual | — | — | — |
| LiveCodeBench | — | — | — |
| Terminal-Bench 2.1 | — | 71.9 | — |
| Aider Polyglot | — | — | — |
| Terminal-Bench 3 | — | — | — |
| BigCodeBench | — | — | — |
| SciCode | — | 42.9 | — |
| CursorBench | — | — | — |
| SWE-Rebench | — | — | — |
| NL2Repo-Bench | — | — | — |
| DeepSWE | — | — | — |
| WebDev Arena | — | — | — |
| Terminal-Bench 4.0 | — | — | — |
| CursorBench 4.0 | — | — | — |
| FrontierCode v1.1 (Main) | — | — | — |
| Arena | |||
| LMArena Elo | — | — | — |
Apertus 8B Instruct
- Context
- 66K
- Parameters
- 8B
- Price
- $0.10 / $0.20
- Speed
- —
- Modalities
- text → text
- License
- Apache 2.0
Fully open, transparent Swiss LLM from EPFL, ETH Zurich, and CSCS — Apache 2.0 weights, training data, and methodology, covering 1,000+ languages.
K2 Horizon 375B A23B
- Context
- 524K
- Parameters
- 375B (23B act.)
- Price
- —
- Speed
- —
- Modalities
- text → text
- License
- Apache 2.0
Flagship model (375B MoE / 23B active) in the Institute of Foundation Models' K2 Horizon fleet, released fully open — weights, code, training data, and methodology — under Apache 2.0.
Benchmark charts
Winner bars are emphasized. Per-benchmark deltas sit above each chart.