Which is better, Claude Opus 4.5 or Kimi K2 (Reasoning)?

Across 44 shared benchmarks tracked on Vector Wire, Claude Opus 4.5 leads on 35 and Kimi K2 (Reasoning) leads on 9 — Claude Opus 4.5 leads on more. Strengths differ by axis; the table below shows every head-to-head number with provenance.

SEEDRefresh Models —Deals —Regulatory —Sources —

Claude Opus 4.5 vs Kimi K2 (Reasoning)

AnthropicvsMoonshot44 shared benchmarks35–9 head-to-head

Benchmark	Claude Opus 4.5	Kimi K2 (Reasoning)
AA Agentic Index	59.6	47.9
AA Intelligence	41.9	33.5
AA-LCR	76	70.3
AA-Omniscience	14	-21.4
AIME 2025	92.8	94.5
AIME25 no tools	91	94.5
Artificial Analysis Coding Index	47.8	34.8
browsecomp	37	60.2
browsecomp_with_context_manager	67.8	60.2
browsecomp_zh	62.4	62.3
critpt	4.6	2.6
frontiermath_tier_4	4.2	0
gdpval	47.3	24.5
GPQA Diamond	87	84.5
HLE	30.8	23.9
HLE (with tools)	43.4	44.9
hmmt_feb_2025	92.9	93.3
hmmt_nov_2025	93.3	89.2
IFBench	58	68.1
imo_answer_bench	84	78.6
LiveCodeBench	87	79.2
LiveCodeBench v6	84.8	83.1
longbench_v2	64.4	45.1
mmlu_redux	95.6	94.4
MMLU-Pro	90	84.6
Multi-SWE-Bench	50	41.9
multichallenge	59	66.4
OJ-Bench (cpp)	54.6	48.7
OmniScience Accuracy	46.6	30.9
OmniScience Non-Hallucination	39	25.8
scicode	50	44.8
Seal-0	47.7	56.3
simplebench	62	39.6
swe_bench_bash	76.8	63.4
SWE-bench Multilingual	77.5	61.1
SWE-bench Verified	81.5	71.3
Terminal-Bench 2.0	59.3	35.7
Terminal-Bench Hard	47	31.1
vectara_answer_rate	98.7	98.6
vectara_avg_summary_length	114.5	59.2
vectara_factual_consistency	89.1	82.1
vectara_hallucination_rate ↓	10.9	17.9
τ²-Bench	98.2	74.3
τ²-Bench Telecom (AA run)	89.5	93

Best tracked score per model per benchmark (default configuration; source-attributed). ↓ marks lower-is-better metrics. Open either model for its full surface, provenance and pricing.