Model comparison

Grok 4.1 Fast vs Grok 4.20 Multi-Agent

Grok 4.20 Multi-Agent is the stronger model overall, scoring 45.5 to 40.9 on the Noometry Index. Grok 4.1 Fast costs 5.7× less per token, which makes it the better buy when Grok 4.20 Multi-Agent's lead doesn't matter for your workload.

Last verified October 10, 2026. 20 shared benchmarks.

Grok 4.1 Fast xAI

40.9

Rank #131 Confirmed

Grok 4.20 Multi-Agent xAI

45.5

Rank #62 Confirmed

Summary

They share 20 benchmarks with published results for both. Grok 4.1 Fast scores higher in 0 categories and Grok 4.20 Multi-Agent in 9 categories; 8 gaps are clear of the uncertainty.
The widest gap is in coding, where Grok 4.20 Multi-Agent leads 42.4 to 33.8.
Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $1.25 / $2.50 for Grok 4.20 Multi-Agent.
Grok 4.20 Multi-Agent accepts more context: 1M tokens versus 128K.

Side by side

Grok 4.1 Fast and Grok 4.20 Multi-Agent specifications
	Grok 4.1 Fast	Grok 4.20 Multi-Agent
Provider	xAI	xAI
Noometry Index	40.9	45.5
Released	2025-06-27	2026-03-09
Weights	Proprietary	Proprietary
Context window	128K	1M
Max output	30K	30K
Input $ / M tokens	$0.20	$1.25
Output $ / M tokens	$0.50	$2.50
Results tracked	32	20

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Category by category

Coding Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 33.8 (#236), Grok 4.20 Multi-Agent: 42.4 (#91)

Coding benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Coding	1411	1458
LMArena WebDev	1241	—
ALE-Bench	394.93	—

Agentic & Tool Use Not comparable

Grok 4.1 Fast: 36.1 (#35), Grok 4.20 Multi-Agent: —

Agentic & Tool Use benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Search	1171	1204
Berkeley Function Calling Leaderboard	69.6%	—
τ²-bench Banking	13.1%	—
Vending-Bench 2	1,107	—

Reasoning Too close to call

Grok 4.1 Fast: 42.3 (#45), Grok 4.20 Multi-Agent: 42.4 (#44)

Reasoning benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
NYT Connections (extended)	87.4%	89.6%
LMArena Hard Prompts	1407	1448
SimpleBench	56%	—
DTBench	87.7%	—
ForecastBench	61	—

Math Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 30.9 (#201), Grok 4.20 Multi-Agent: 36.6 (#106)

Math benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Math	1408	1441
MathArena Final-Answer Competitions	60.9%	—
ProofBench	4%	—

Knowledge Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 32.6 (#203), Grok 4.20 Multi-Agent: 39.7 (#116)

Knowledge benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Expert	1398	1445
Vectara Hallucination Rate	17.8%	—

Multimodal Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 36.3 (#71), Grok 4.20 Multi-Agent: 39.8 (#44)

Multimodal benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Vision	1201	1259

Multilingual Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 51.1 (#110), Grok 4.20 Multi-Agent: 54.6 (#40)

Multilingual benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Non-English	1391	1440
LMArena Chinese	1441	1475
LMArena French	1416	1467
LMArena German	1404	1456
LMArena Japanese	1347	1405
LMArena Korean	1361	1416
LMArena Russian	1387	1457
LMArena Spanish	1411	1447

Instruction Following Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 72.8 (#127), Grok 4.20 Multi-Agent: 75.0 (#80)

Instruction Following benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Instruction Following	1376	1420

Long Context Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 42.4 (#121), Grok 4.20 Multi-Agent: 43.7 (#84)

Long Context benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Longer Query	1390	1430

Writing & Preference Grok 4.20 Multi-Agent leads

Grok 4.1 Fast: 57.4 (#126), Grok 4.20 Multi-Agent: 64.1 (#57)

Writing & Preference benchmarks
Benchmark	Grok 4.1 Fast	Grok 4.20 Multi-Agent
LMArena Text	1408	1450
LMArena Creative Writing	1394	1435
LMArena Multi-Turn	1389	1451
EQ-Bench Creative Writing	1327	—

Frequently asked questions

Is Grok 4.1 Fast better than Grok 4.20 Multi-Agent?

Which is cheaper, Grok 4.1 Fast or Grok 4.20 Multi-Agent?

Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Grok 4.20 Multi-Agent lists at $1.25 and $2.50.

Is Grok 4.1 Fast or Grok 4.20 Multi-Agent better for coding?

Grok 4.20 Multi-Agent scores higher on coding benchmarks: 42.4 versus 33.8 in the Noometry coding category.

Which has the bigger context window?

Grok 4.20 Multi-Agent does, with 1M tokens against 128K.

How many benchmarks do Grok 4.1 Fast and Grok 4.20 Multi-Agent share?

20 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Grok 4.20 Multi-Agent has 20.