Model Comparison

Grok 4.5 (high)
vs. GPT-5.5 (xhigh)

Comparing 2 AI models · 7 benchmarks · SpaceXAI, OpenAI

Recommended Pick

OpenAI logoGPT-5.5 (xhigh)7 metric wins

Strongest on: Reasoning, Intelligence, Coding

Best Value

SpaceXAI logo

Grok 4.5 (high)

100.0 value score

62.4 reasoning / $3.00/1M

Lowest Price

SpaceXAI logo

Grok 4.5 (high)

$2.00/1M input price

Best Reasoning

OpenAI logo

GPT-5.5 (xhigh)

64.2 reasoning score

Blends available reasoning benchmarks

Best for Coding

OpenAI logo

GPT-5.5 (xhigh)

74.9 coding index

Composite Indices

Higher is better; speed and price are normalized

Standard Benchmarks

Only benchmarks with data are shown

Differences That Matter

Best value

Grok 4.5 (high) has the strongest quality-to-price mix at 100.0 out of 100 value points.

Price gap

Grok 4.5 (high) is 2.5x cheaper on input tokens than GPT-5.5 (xhigh).

Speed gap

Grok 4.5 (high) generates about 1.5x as many tokens per second as GPT-5.5 (xhigh).

Reasoning gap

GPT-5.5 (xhigh) leads Grok 4.5 (high) by 1.8 points on reasoning.

Coding gap

GPT-5.5 (xhigh) leads Grok 4.5 (high) by 2.5 points on coding.

Live compare

Response Face-Off

Run one prompt through the selected models and compare response quality with live speed and cost context.

SpaceXAI logo

Grok 4.5 (high)

SpaceXAI

Waiting

TTFT

Time

tok/s

Tokens

Cost

Waiting
OpenAI logo

GPT-5.5 (xhigh)

OpenAI

Waiting

TTFT

Time

tok/s

Tokens

Cost

Waiting

Which answer was more useful?

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Full Comparison

Metric
SpaceXAI logoGrok 4.5 (high)
SpaceXAI
Top Pick
OpenAI logoGPT-5.5 (xhigh)
OpenAI
Pricing per 1M tokens
Input Cost$2.00/1M$5.00/1M
Output Cost$6.00/1M$30.00/1M
Blended (3:1)$3.00/1M$11.25/1M
Specifications
OrganizationSpaceXAIOpenAI
Release DateJul 8, 2026Apr 23, 2026
Performance & Speed
Throughput109.6 tok/s72.0 tok/s
TTFT13452ms24952ms
Latency13452ms24952ms
Composite Indices
Value Score100.027.4
Reasoning Score62.464.2
Intelligence53.854.8
Coding72.474.9
Standard Benchmarks
GPQA93.1%93.5%
HLE40.3%44.3%
SciCode54.1%56.1%
LCR67.7%74.3%
IFBench75.9%
TAU-bench v293.9%
TerminalBench Hard60.6%

Key Takeaways

Grok 4.5 (high) offers the best value at $2.00/1M,making it ideal for high-volume applications and cost-conscious projects.

GPT-5.5 (xhigh) has the strongest reasoning profile with a 64.2 reasoning score,combining the available reasoning-heavy benchmarks.

GPT-5.5 (xhigh) reaches a 74.9 coding index,making it the top choice for software development and code generation tasks.

All models support context windows of ∞+ tokens,suitable for processing lengthy documents and maintaining extended conversations.

When to Choose Each Model

SpaceXAI logo

Grok 4.5 (high)

  • Cost-sensitive applications
  • High-volume processing
OpenAI logo

GPT-5.5 (xhigh)

  • Complex reasoning tasks
  • Research & analysis
  • Code generation
  • Software development