Model comparison

Grok 4.20 Multi-Agent vs Step 3.5 Flash

Grok 4.20 Multi-Agent is the stronger model overall, scoring 46.2 to 42.3 on the Noometry Index. Step 3.5 Flash costs 10× 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. 18 shared benchmarks.

Grok 4.20 Multi-Agent xAI

46.2

Rank #65 Confirmed

Step 3.5 Flash

StepFun

42.3

Rank #116 Confirmed

Summary

They share 18 benchmarks with published results for both. Grok 4.20 Multi-Agent scores higher in 7 categories and Step 3.5 Flash in 1 category; 5 gaps are clear of the uncertainty.
The widest gap is in reasoning, where Grok 4.20 Multi-Agent leads 43.9 to 22.2.
The biggest single-benchmark swing is NYT Connections (extended): 89.6% for Grok 4.20 Multi-Agent and 28.4% for Step 3.5 Flash.
Step 3.5 Flash is cheaper at $0.10 / $0.30 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 256K.
Step 3.5 Flash has downloadable open weights; the other is API-only.

Side by side

Grok 4.20 Multi-Agent and Step 3.5 Flash specifications
	Grok 4.20 Multi-Agent	Step 3.5 Flash
Provider	xAI	StepFun
Noometry Index	46.2	42.3
Released	2026-03-09	2026-01-29
Weights	Proprietary	Open
Context window	1M	256K
Max output	30K	256K
Input $ / M tokens	$1.25	$0.10
Output $ / M tokens	$2.50	$0.30
Results tracked	20	19

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Category by category

Coding Too close to call

Grok 4.20 Multi-Agent: 43.0 (#92), Step 3.5 Flash: 42.4 (#105)

Coding benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Coding	1457	1436

Agentic & Tool Use Not comparable

Grok 4.20 Multi-Agent: —, Step 3.5 Flash: —

Agentic & Tool Use benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Search	1204	—

Reasoning Grok 4.20 Multi-Agent leads

Grok 4.20 Multi-Agent: 43.9 (#48), Step 3.5 Flash: 22.2 (#202)

Reasoning benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
NYT Connections (extended)	89.6%	28.4%
LMArena Hard Prompts	1448	1411

Math Step 3.5 Flash leads

Grok 4.20 Multi-Agent: 39.4 (#104), Step 3.5 Flash: 42.6 (#84)

Math benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Math	1442	1408
MathArena Final-Answer Competitions	—	66.8%

Knowledge Too close to call

Grok 4.20 Multi-Agent: 40.4 (#119), Step 3.5 Flash: 39.6 (#132)

Knowledge benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Expert	1445	1421

Multimodal Not comparable

Grok 4.20 Multi-Agent: 40.5 (#48), Step 3.5 Flash: —

Multimodal benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Vision	1259	—

Multilingual Grok 4.20 Multi-Agent leads

Grok 4.20 Multi-Agent: 54.4 (#43), Step 3.5 Flash: 50.5 (#119)

Multilingual benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Non-English	1440	1385
LMArena Chinese	1475	1447
LMArena French	1466	1421
LMArena German	1456	1405
LMArena Japanese	1405	1354
LMArena Korean	1416	1352
LMArena Russian	1457	1385
LMArena Spanish	1447	1419

Instruction Following Grok 4.20 Multi-Agent leads

Grok 4.20 Multi-Agent: 74.8 (#84), Step 3.5 Flash: 73.1 (#124)

Instruction Following benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Instruction Following	1420	1385

Long Context Too close to call

Grok 4.20 Multi-Agent: 43.7 (#88), Step 3.5 Flash: 42.8 (#117)

Long Context benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Longer Query	1431	1402

Writing & Preference Grok 4.20 Multi-Agent leads

Grok 4.20 Multi-Agent: 64.0 (#59), Step 3.5 Flash: 58.8 (#113)

Writing & Preference benchmarks
Benchmark	Grok 4.20 Multi-Agent	Step 3.5 Flash
LMArena Text	1450	1403
LMArena Creative Writing	1436	1357
LMArena Multi-Turn	1452	1405

Frequently asked questions

Is Grok 4.20 Multi-Agent better than Step 3.5 Flash?

Which is cheaper, Grok 4.20 Multi-Agent or Step 3.5 Flash?

Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; Grok 4.20 Multi-Agent lists at $1.25 and $2.50.

Is Grok 4.20 Multi-Agent or Step 3.5 Flash better for coding?

They score almost the same on coding (43.0 vs 42.4); test both on your own repository before choosing.

Which has the bigger context window?

Grok 4.20 Multi-Agent does, with 1M tokens against 256K.

How many benchmarks do Grok 4.20 Multi-Agent and Step 3.5 Flash share?

18 benchmarks have published results for both models. Grok 4.20 Multi-Agent has 20 scored results on Noometry and Step 3.5 Flash has 19.