Noometry

Model comparison

C4ai Aya Expanse 8b vs Kimi K2 (Jul 2025)

Kimi K2 (Jul 2025) is the stronger model overall, scoring 41.2 to 34.9 on the Noometry Index.

Last verified . 15 shared benchmarks.

C4ai Aya Expanse 8b Cohere

34.9

Rank #229 Confirmed

Kimi K2 (Jul 2025) Moonshot AI

41.2

Rank #140 Confirmed

Summary

  • They share 15 benchmarks with published results for both. C4ai Aya Expanse 8b scores higher in 0 categories and Kimi K2 (Jul 2025) in 8 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in writing & preference, where Kimi K2 (Jul 2025) leads 62.3 to 39.0.
  • The biggest single-benchmark swing is Vectara Hallucination Rate: 9.5% for C4ai Aya Expanse 8b and 17.9% for Kimi K2 (Jul 2025).

Side by side

C4ai Aya Expanse 8bKimi K2 (Jul 2025)
ProviderCohereMoonshot AI
Noometry Index34.941.2
Released—2025-07-12
WeightsOpenOpen
Context window—262K
Max output—262K
Input $ / M tokens—$0.57
Output $ / M tokens—$2.30
Results tracked1542

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Category by category

Coding Kimi K2 (Jul 2025) leads

C4ai Aya Expanse 8b: 33.8 (#252), Kimi K2 (Jul 2025): 42.4 (#102)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
LMArena Coding11601399
SWE-bench Verified (bash only)—63.4%
Aider Polyglot—59.1%
GSO—4.9%
WeirdML—42.8%
ALE-Bench—597.5

Agentic & Tool Use Not comparable

C4ai Aya Expanse 8b: —, Kimi K2 (Jul 2025): 32.4 (#64)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
Terminal-Bench—35.7%
Berkeley Function Calling Leaderboard—59.1%
METR Time Horizons—59.2%

Reasoning Too close to call

C4ai Aya Expanse 8b: 22.4 (#197), Kimi K2 (Jul 2025): 23.3 (#179)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
LMArena Hard Prompts11561384
SimpleBench—26.3%
Kagi LLM Benchmark—64.4%
Epoch Capabilities Index—146.01
ForecastBench—60.2

Math Kimi K2 (Jul 2025) leads

C4ai Aya Expanse 8b: 33.3 (#203), Kimi K2 (Jul 2025): 42.7 (#83)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
LMArena Math11681397
Omni-MATH—65.4%
FrontierMath (Feb 2025 set)—21.4%
FrontierMath Tier 4 (v1)—0%

Knowledge Kimi K2 (Jul 2025) leads

C4ai Aya Expanse 8b: 33.6 (#201), Kimi K2 (Jul 2025): 37.3 (#157)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
Vectara Hallucination Rate9.5%17.9%
LMArena Expert11531365
MMLU-Pro—81.9%
Confabulations—20.4%
GPQA (HELM)—65.3%

Multilingual Kimi K2 (Jul 2025) leads

C4ai Aya Expanse 8b: 36.1 (#242), Kimi K2 (Jul 2025): 49.6 (#130)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
LMArena Non-English11801372
LMArena Chinese11811415
LMArena German11881387
LMArena Japanese11201349
LMArena Russian11971385
LMArena French—1379
LMArena Korean—1325
LMArena Spanish—1386

Instruction Following Kimi K2 (Jul 2025) leads

C4ai Aya Expanse 8b: 60.1 (#253), Kimi K2 (Jul 2025): 71.1 (#156)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
LMArena Instruction Following11551348
IFEval—85%

Long Context Kimi K2 (Jul 2025) leads

C4ai Aya Expanse 8b: 36.1 (#236), Kimi K2 (Jul 2025): 41.2 (#145)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
LMArena Longer Query11911353
Fiction.LiveBench—66.7%
CL-bench—17.6%

Writing & Preference Kimi K2 (Jul 2025) leads

C4ai Aya Expanse 8b: 39.0 (#250), Kimi K2 (Jul 2025): 62.3 (#78)

BenchmarkC4ai Aya Expanse 8bKimi K2 (Jul 2025)
LMArena Text11851380
LMArena Creative Writing11681350
LMArena Multi-Turn11601371
Short-Story Creative Writing—85.6%
EQ-Bench Creative Writing—1666
WildBench—86.2%

Frequently asked questions

Is C4ai Aya Expanse 8b better than Kimi K2 (Jul 2025)?

Kimi K2 (Jul 2025) is the stronger model overall, scoring 41.2 to 34.9 on the Noometry Index.

Is C4ai Aya Expanse 8b or Kimi K2 (Jul 2025) better for coding?

Kimi K2 (Jul 2025) scores higher on coding benchmarks: 42.4 versus 33.8 in the Noometry coding category.

How many benchmarks do C4ai Aya Expanse 8b and Kimi K2 (Jul 2025) share?

15 benchmarks have published results for both models. C4ai Aya Expanse 8b has 15 scored results on Noometry and Kimi K2 (Jul 2025) has 42.

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