Claude Sonnet 5.5 vs K2-V2: Release Comparison

Name: Intelligence
Creator: Artificial Analysis
License: https://artificialanalysis.ai/docs/legal/Terms-of-Use.pdf

Comparison of the Claude Sonnet 5.5 and K2-V2 releases: 5 and 3 models respectively, each with different intelligence, performance, and pricing characteristics. Below is a comparison of the key metrics across all 8 models.

For intelligence, Claude Sonnet 5.5 scores highest: Claude Sonnet 5.5 (Max, Default Fallback) at 56, against K2-V2 (High) at 10 for K2-V2.

Model Playground

Releases compared


	Claude Sonnet 5.5 (max with fallback)	Claude Sonnet 5.5 (xhigh with fallback)	Claude Sonnet 5.5 (high with fallback)	Claude Sonnet 5.5 (medium with fallback)	Claude Sonnet 5.5 (low with fallback)	K2-V2 (high)	K2-V2 (medium)	K2-V2 (low)
Intelligence Index	56	52	47	41	36	10*	9*	7*
Finance & Accounting	57	52	47	41	38	--	--	--
Strategy & Ops	60	56	52	45	41	--	--	--
Legal	56	52	49	44	41	--	--	--
Healthcare & Medical	58	--	--	--	--	--	--	--
Engineering	58	54	48	42	38	--	--	--
Economics	61	56	52	47	44	--	--	--
AA-Briefcase v1.1	1817	1751	1636	1441	1272	--	--	--
GDPval-AA v2.1	1838	1728	1549	1323	1175	--	--	--
AutomationBench-AA	71.8%	65.5%	59.4%	54.9%	49.4%	--	--	--
Terminal-Bench 4.0	63.6%	57.1%	43.9%	29.8%	20.7%	--	--	--
SciCode	61.0%	57.3%	53.7%	52.9%	49.1%	--	--	--
Humanity's Last Exam	55.0%	50.0%	45.8%	39.8%	36.2%	10.5%	4.4%	3.6%
GDP.pdf	25.8%	24.6%	25.2%	20.2%	16.0%	--	--	--
CritPt	31.4%	31.1%	24.6%	16.9%	11.4%	0.0%	0.0%	0.0%
AA-Omniscience	32	24	21	20	19	−56	−49	−47
AA-LCR v1.1	82.7%	79.7%	78.0%	76.3%	76.0%	35.0%	28.0%	20.3%

Cost per TaskUSD	$5.46	$2.01	$0.88	$0.48	$0.35	--	--	--
Input PriceUSD/1M Tokens	$2.00	$2.00	$2.00	$2.00	$2.00	--	--	--
Output PriceUSD/1M Tokens	$10.00	$10.00	$10.00	$10.00	$10.00	--	--	--
Cache Hit PriceUSD/1M Tokens	$0.10	$0.10	$0.10	$0.10	$0.10	--	--	--
Cache Write PriceUSD/1M Tokens	$2.50	$2.50	$2.50	$2.50	$2.50	--	--	--

Output SpeedTokens/s	136	112	106	108	109	--	--	--
Time to First Tokens	394.52	31.59	11.01	1.80	1.17	--	--	--
Time to First Answer Tokens	394.52	31.59	11.01	1.80	1.17	--	--	--
End-to-End Response Times	398.18	36.05	15.71	6.43	5.76	--	--	--
Time per Tasks	897.39	418.05	216.82	122.29	82.15	--	--	--

Context Window	1M	1M	1M	1M	1M	512k	512k	512k
Creator	Anthropic	Anthropic	Anthropic	Anthropic	Anthropic	Institute of Foundation Models	Institute of Foundation Models	Institute of Foundation Models
License	Proprietary	Proprietary	Proprietary	Proprietary	Proprietary	Open	Open	Open
Input Modality	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text	Supports: text	Supports: text
Output Modality	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text
Providers						--	--	--

* Estimated

Intelligence

Artificial Analysis Intelligence Index · Higher is better

Speed

Output tokens per second · Higher is better

Cost per Task

Weighted average cost (USD) per Intelligence Index task · Lower is better

Intelligence

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index v4.3.2 incorporates 10 evaluations: AA-Briefcase v1.1, GDPval-AA v2.1, AutomationBench-AA, Terminal-Bench 4.0, SciCode, Humanity's Last Exam, GDP.pdf, CritPt, AA-Omniscience, AA-LCR v1.1

Estimate (independent evaluation forthcoming)

Artificial Analysis Intelligence Index v4.3.2 includes: AA-Briefcase v1.1, GDPval-AA v2.1, AutomationBench-AA, Terminal-Bench 4.0, SciCode, Humanity's Last Exam, GDP.pdf, CritPt, AA-Omniscience, AA-LCR v1.1. See Intelligence Index methodology for further details, including a breakdown of each evaluation and how we run them.

Intelligence Index vs. Cost per Task

Artificial Analysis Intelligence Index · Weighted average cost (USD) per Artificial Analysis Intelligence Index task

Most attractive quadrant

Claude Sonnet 5.5

Pareto line

AA-Briefcase v1.1

GDPval-AA v2.1

Cost per Task (USD, Log Scale)

Weighted average cost per Intelligence Index task. Each evaluation’s cost is calculated from input, cache hit, cache write, reasoning, and answer token prices, divided by task count, and weighted by its Intelligence Index weight.

Cost

Cost per Intelligence Index Task

Weighted average cost (USD) per Intelligence Index task · Segmented by token type · Lower is better

Speed & Latency

Output Speed

Output tokens per second · Higher is better

Tokens per second received while the model is generating tokens (ie. after first chunk has been received from the API for models which support streaming).

Figures represent performance of the model's first-party API or the median across providers where a first-party API is not available.

Capability Scores

Capability Indexes

Measures the performance of models on specific capabilities and industries

Finance & Accounting Index

Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, Humanity's Last Exam, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better

Strategy & Ops Index

Incorporates 6 evaluations: GDPval-AA v2.1, AA-Briefcase v1.1, AA-Omniscience, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better

Legal Index

Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, Humanity's Last Exam, AA-LCR v1.1, GDP.pdf, AutomationBench-AA · Higher is better

Healthcare & Medical Index

Incorporates 6 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, MLCR-AA, Humanity's Last Exam, AutomationBench-AA · Higher is better

Engineering Index

Incorporates 6 evaluations: AA-Omniscience, Humanity's Last Exam, CritPt, GDPval-AA v2.1, AA-Briefcase v1.1, Terminal-Bench 4.0 · Higher is better

Economics Index

Incorporates 5 evaluations: AA-Omniscience, Humanity's Last Exam, GDPval-AA v2.1, AA-Briefcase v1.1, AA-LCR v1.1 · Higher is better

AA-PersonalityBenchNew

Model AvsModel B

AA-PersonalityBench results are not available for K2-V2

Claude Sonnet 5.5 vs K2-V2: Release Comparison

Intelligence

Speed

Cost per Task

Intelligence

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index

Intelligence Index vs. Cost per Task

Cost per Intelligence Index Task

Artificial Analysis Intelligence Index

Cost

Cost per Intelligence Index Task

Cost per Intelligence Index Task

Speed & Latency

Output Speed

Output Speed

Model Performance Representation

Capability Scores

Capability Indexes

AA-PersonalityBenchNew