Context Window

Compare

Gpt 4o Realtime Preview 2025 06 03 vs Grok 4 1 Fast Non Reasoning Latest

This page is context-first: how much text each model can take in one request. Full specs adds capabilities and limits; the pricing matrix below is only about $/million tokens from hosts that list both models.

Openai

Model

Gpt 4o Realtime Preview 2025 06 03

Tool calling

Context window

128K

128,000 tokens · ~96K words

Model page
Xai

Model

Grok 4 1 Fast Non Reasoning Latest

Image inputTool calling

Context window

2M

2,000,000 tokens · ~1.5M words

Model page

Context window · side by side

Bar length is relative to the larger of the two windows (100% = max of this pair). This is not pricing.

Gpt 4o Realtime Preview 2025 06 03128K
Grok 4 1 Fast Non Reasoning Latest2M

Grok 4 1 Fast Non Reasoning Latest has about 15.6× the context window of the other in this pair.

Token calculator →Memory savings →

Grok 4 1 Fast Non Reasoning Latest has 1462% more context capacity (2000K vs 128K tokens). Grok 4 1 Fast Non Reasoning Latest is 96% cheaper on input.

Quick verdicts

Short takeaways — validate with your own workloads.

  • Long document processing

    Use Grok 4 1 Fast Non Reasoning Latest. Its 2000K context fits entire documents without chunking (vs 128K).

  • RAG / high-volume retrieval

    Use Grok 4 1 Fast Non Reasoning Latest. Input tokens are 96% cheaper — critical when sending large retrieved contexts.

  • Long output (reports, code files)

    Use Grok 4 1 Fast Non Reasoning Latest. Its 2000K max output lets you generate complete artifacts in one request.

Full specs

Context, output, capabilities, and dates. Green highlights the favorable value where we compute a winner.

SpecGpt 4o Realtime Preview 2025 06 03Grok 4 1 Fast Non Reasoning Latest
Context window128,000 tokens (128K)2,000,000 tokens (2000K)
Max output tokens4,096 tokens (4K)2,000,000 tokens (2000K)
Speed tierBalancedDeep
VisionNoYes
Function callingYesYes
Extended thinkingNoNo
Prompt cachingYesYes
Batch APIYesNo
Release dateN/AN/A

Pricing matrix

Dollar rates only: hosts that list both models, per 1M tokens. For how much text fits, use the context section above — not this table.

ProviderGpt 4o Realtime Preview 2025 06 03 inGpt 4o Realtime Preview 2025 06 03 outGrok 4 1 Fast Non Reasoning Latest inGrok 4 1 Fast Non Reasoning Latest out
Openai$5.00/M$20.00/M——
Xai——$0.200/M$0.500/M

Frequently asked questions

Grok 4 1 Fast Non Reasoning Latest has a larger context window: 2000K tokens vs 128K. For long documents, large codebases, or extended agent sessions, the larger context window reduces the need to chunk inputs or summarize history.

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Example: a multi-turn chat session

Without Mem0~128K tokens sent
Full history
Repeated info
Old context
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Key memories
Current turn

80% less to send — works with any model