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GPT-5.1-Codex-Max vs Grok 4.5

vs
Grok 4.5

xAI

88#22
Signal-by-Signal Comparison
SignalGPT-5.1-Codex-MaxDeltaGrok 4.5
Capabilities
100
--
100
Benchmarks
88
+2
86
Pricing
90
-4
94
Context window size
80
-1
81
Recency
93
-7
100
Output Capacity
85
+65
20
Overall Result
2 wins
of 6
3 wins
Grok 4.5 wins 3 of 6 signals

Score History

Score History (21 data points)
GPT-5.1-Codex-MaxGrok 4.5
GPT-5.1-Codex-Max

87.4

current score

Leader

Grok 4.5

right now

Grok 4.5

87.8

current score

LMMarketCap.com
Interactive Price Comparison
100Kcalls/month
1,000tokens (~1,333 chars)
500tokens (~667 chars)

GPT-5.1-Codex-Max

OpenAI

Per request$0.006250
Daily$20.83
Monthly$625.00
Annual$7500.00

Grok 4.5

xAI

Best Value
Per request$0.005000
Daily$16.67
Monthly$500.00
Annual$6000.00

Grok 4.5 saves you $125.00/month

That's $1500.00/year compared to GPT-5.1-Codex-Max at your current usage level of 100K calls/month.

20% cheaper
Choose Grok 4.5 for cost optimization

GPT-5.1-Codex-Max pricing:
Input:$1.25/M tokens
Output:$10.00/M tokens
Grok 4.5 pricing:
Input:$2.00/M tokens
Output:$6.00/M tokens
GPT-5.1-Codex-Max

OpenAI

87

Composite Score

Winner
Grok 4.5

xAI

88

Composite Score

Signal-by-Signal Comparison
MetricGPT-5.1-Codex-MaxGrok 4.5Winner
Overall Score
87
88
Grok 4.5
Rank#24#22
Grok 4.5
Quality Rank#24#22
Grok 4.5
Adoption Rank#24#22
Grok 4.5
Parameters------
Context Window400K500K
Grok 4.5
Pricing$1.25/$10.00/M$2.00/$6.00/M--
Signal Scores
Capabilities
100
100
GPT-5.1-Codex-Max
Benchmarks
88
86
GPT-5.1-Codex-Max
Pricing
90
94
Grok 4.5
Context window size
80
81
Grok 4.5
Recency
93
100
Grok 4.5
Output Capacity
85
20
GPT-5.1-Codex-Max
Benchmark Head-to-Head(12 benchmarks)
GPT-5.1-Codex-Max: 9Grok 4.5: 1
GPT-5.1-Codex-Max
Grok 4.5
Normalized 0-100%
MMLU
93.2%91.5%
MMLU-Pro
85%83.5%
GPQA Diamond
86.5%82%
MATH-500
93.5%95%
HumanEval
96.8%95.5%
SWE-bench Verified
76.5%70%
AIME 2024
-88%
IFEval
92.5%91%
BBH
91%90%
Arena Elo
14751462
LiveBench
74%73%
HLE
23.68%-
Benchmark Interpretation

Our score (0-100) is driven by benchmark performance (90%) from Arena Elo ratings, MMLU, GPQA, HumanEval, SWE-bench, and 15+ standardized evaluations. Capabilities and context window serve as tiebreakers (10%). Learn more about our methodology.

GPT-5.1-Codex-MaxElite Tier

Scores 87/100 (rank #24), placing it in the top 92% of all 290 models tracked.

Raw Quality0/100
Cost Efficiency0/100
Speed0/100
Grok 4.5Elite Tier

Scores 88/100 (rank #22), placing it in the top 93% of all 290 models tracked.

Raw Quality0/100
Cost Efficiency0/100
Speed0/100

With only a 0-point gap, these models are in the same performance tier. The practical difference in output quality is minimal - your choice should depend on pricing, latency requirements, and specific feature needs.

When to Use Each Model

Choose GPT-5.1-Codex-Max when you need:

  • Step-by-step reasoning and chain-of-thought problem solving

Choose Grok 4.5 when you need:

  • High-volume production workloads where API costs must be minimized
  • Step-by-step reasoning and chain-of-thought problem solving
Cost-Performance Analysis
GPT-5.1-Codex-Max
Input cost$1.25/M tokens
Output cost$10.00/M tokens
Cost per quality point$0.129
Est. monthly (1M tokens/day)$168.75
Grok 4.5Best Value
Input cost$2.00/M tokens
Output cost$6.00/M tokens
Cost per quality point$0.091
Est. monthly (1M tokens/day)$120.00

Grok 4.5 offers 29% better value per quality point. At 1M tokens/day, you'd spend $120.00/month with Grok 4.5 vs $168.75/month with GPT-5.1-Codex-Max - a $48.75 monthly difference.

Latency & Speed
GPT-5.1-Codex-MaxFaster
Speed score0/100
Grok 4.5
Speed score0/100

Both models have comparable response speeds. For most applications, the latency difference is negligible.

When latency matters most: Interactive chatbots, IDE code completion, real-time translation, and user-facing applications where response time directly impacts experience. For batch processing, background summarization, or offline analysis, latency is less critical.

Example Use Cases

Code generation & review

Based on overall model capabilities and architecture for coding tasks like generating functions, debugging, and refactoring

GPT-5.1-Codex-Max

Customer support chatbot

Suitable for user-facing chat with competitive response times. Grok 4.5 also offers lower per-token costs for high-volume support

GPT-5.1-Codex-Max

Long document analysis

Larger context window (500K tokens) can process longer documents, contracts, and research papers in a single pass

Grok 4.5

Batch data extraction

Lower output pricing ($6.00/M) reduces costs when processing thousands of records daily

Grok 4.5

Creative writing & content

Higher overall composite score (88/100) correlates with better nuance, coherence, and style in long-form content

Grok 4.5

Image understanding & OCR

Supports vision input - can analyze screenshots, diagrams, photos, and scanned documents directly

GPT-5.1-Codex-Max
Which Should You Choose?
Our recommendation:
Grok 4.5

GPT-5.1-Codex-Max and Grok 4.5 are extremely close in overall performance (only 0.3999999999999915 points apart). Your best choice depends entirely on which specific strengths matter most for your use case.

by OpenAI

  • Choose for Quality - Marginally better benchmark scores; both are excellent
  • Choose for Reliability - Higher uptime and faster response speeds
  • Choose for Prototyping - Stronger community support and better developer experience
  • Choose for Production - Wider enterprise adoption and proven at scale
Grok 4.5
Recommended

by xAI

  • Choose for Cost - 29% lower pricing; better value at scale
Capability Comparison
CapabilityGPT-5.1-Codex-MaxGrok 4.5
Vision (Image Input)
Function Calling
Streaming
JSON Mode
Reasoning
Web Search
Image Output
Monthly Cost Calculator
1,000tokens (600 in / 400 out)
100requests/day (3,000/month)

GPT-5.1-Codex-Max

OpenAI

$14.25
estimated monthly cost

Grok 4.5

xAI

Best Value
$10.80
estimated monthly cost

Grok 4.5 saves you $3.45/month

That's 24% cheaper than GPT-5.1-Codex-Max at 1,000 tokens/request and 100 requests/day.

Assumes 60% input / 40% output token ratio per request. Actual costs may vary based on your usage pattern.

Parameters & Context
ParameterGPT-5.1-Codex-MaxGrok 4.5
Context Window400K500K
Max Output Tokens128,000--
Open SourceNoNo
CreatedDec 4, 2025Jul 8, 2026
Last updated: 33m ago

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