Gemini 3.8 Flash vs GPT-5.6 Luna: Release Comparison

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

Comparison of the Gemini 3.8 Flash and GPT-5.6 Luna releases: 3 and 6 models respectively, each with different intelligence, performance, and pricing characteristics. Below is a comparison of the key metrics across all 9 models.

For intelligence, Gemini 3.8 Flash scores highest: Gemini 3.8 Flash (high) at 41, against GPT-5.6 Luna (max) at 38 for GPT-5.6 Luna.
For output speed, Gemini 3.8 Flash is fastest: Gemini 3.8 Flash (high) at 341 t/s, against GPT-5.6 Luna (max) at 119 t/s for GPT-5.6 Luna.
For cost per task, GPT-5.6 Luna is cheapest: GPT-5.6 Luna (low) at $0.01, against Gemini 3.8 Flash (medium) at $0.93 for Gemini 3.8 Flash.

Releases compared

Intelligence

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index v4.3 incorporates 10 evaluations: AA-Briefcase, GDPval-AA v2, AutomationBench-AA, Terminal-Bench 4.0, SciCode, Humanity's Last Exam, GDP.pdf, CritPt, AA-Omniscience, AA-LCR v1.1

Artificial Analysis Intelligence Index v4.3 includes: AA-Briefcase, GDPval-AA v2, 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 Intelligence Index Task

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

Most attractive quadrant

Gemini 3.8 Flash

GPT-5.6 Luna

Pareto line

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 Artificial Analysis 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 (e.g. OpenAI for o1) or the median across providers where a first-party API is not available (e.g. Meta's Llama models).

Capability Scores

Capability Indices

Measures the performance of models on specific capabilities and industries

Finance & Accounting Index

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

Strategy & Ops Index

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

Legal Index

Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2, AA-Briefcase, 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, AA-Briefcase, 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, AA-Briefcase, Terminal-Bench 4.0 · Higher is better

Economics Index

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

Further details


																												Input modality	Output modality	Weights		Provider Benchmarks
Gemini 3.8 Flash (high)	Google	41	47	49	52	42	43	53	$1.24	$0.6	$0.75	$3.75	$0.075	$1,623	71k	43k	172M	341	20.55s	20.55s	22.02s	201.93s	-	1M	Sep 2026	-	Yes	Supports: text, image, speech, and video	Supports: text	Not available	-	View
Gemini 3.8 Flash (medium)	Google	40	45	49	51	-	41	51	$0.93	$0.6	$0.75	$3.75	$0.075	$1,100	53k	27k	95M	-	-	-	-	-	-	1M	Sep 2026	-	Yes	Supports: text, image, speech, and video	Supports: text	Not available	-	View
GPT-5.6 Luna (max)	OpenAI	38	-	-	-	-	36	43	$0.18	$0.2	$0.20	$1.20	$0.02	$320	41k	28k	154M	119	125.76s	125.76s	129.96s	348.69s	-	1M	Jul 2026	-	Yes	Supports: text and image	Supports: text	Not available	-	View
GPT-5.6 Luna (xhigh)	OpenAI	35	38	41	35	33	34	41	$0.09	$0.2	$0.20	$1.20	$0.02	$179	24k	15k	85M	119	39.58s	39.58s	43.78s	197.72s	-	1M	Jul 2026	-	Yes	Supports: text and image	Supports: text	Not available	-	View
Gemini 3.8 Flash (low)	Google	34	40	39	45	-	35	46	-	$0.6	$0.75	$3.75	$0.075	-	-	-	-	-	-	-	-	-	-	1M	Sep 2026	-	Yes	Supports: text, image, speech, and video	Supports: text	Not available	-	View
GPT-5.6 Luna (high)	OpenAI	32	35	37	33	30	32	38	$0.04	$0.2	$0.20	$1.20	$0.02	$108	14k	7k	50M	114	8.57s	8.57s	12.94s	127.33s	-	1M	Jul 2026	-	Yes	Supports: text and image	Supports: text	Not available	-	View
GPT-5.6 Luna (medium)	OpenAI	25	27	29	28	25	27	32	$0.02	$0.2	$0.20	$1.20	$0.02	$44	4k	2k	18M	111	2.44s	2.44s	6.94s	39.42s	-	1M	Jul 2026	-	Yes	Supports: text and image	Supports: text	Not available	-	View
GPT-5.6 Luna (low)	OpenAI	22	24	23	25	21	23	29	$0.01	$0.2	$0.20	$1.20	$0.02	$27	3k	559	10M	102	1.98s	1.98s	6.86s	24.23s	-	1M	Jul 2026	-	Yes	Supports: text and image	Supports: text	Not available	-	View
GPT-5.6 Luna (Non-reasoning)	OpenAI	16	17	15	18	-	19	22	$0.01	$0.2	$0.20	$1.20	$0.02	$23	2k	0	5M	105	0.78s	0.78s	5.55s	19.30s	-	1M	Jul 2026	-	No	Supports: text and image	Supports: text	Not available	-	View

Gemini 3.8 Flash vs GPT-5.6 Luna: Release Comparison

Intelligence

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index

Intelligence Index vs. Cost per Intelligence Index 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 Indices

Further details