Compare/GPT-5.6 Luna (max) vs Grok 4.5 (high)

GPT-5.6 Luna (max)vsGrok 4.5 (high)

Side-by-side comparison of pricing, 12 benchmarks, and generation speed.

OpenAI

GPT-5.6 Luna (max)

Input
$1/M
Output
$6/M
Speed
264 tok/s
TTFT
45.96s
SpaceXAI

Grok 4.5 (high)

Input
$2/M
Output
$6/M
Speed
120 tok/s
TTFT
16.24s

Winner by Category

Cheaper
GPT-5.6 Luna (max)
Faster (tok/s)
GPT-5.6 Luna (max)
Lower Latency
Grok 4.5 (high)
Benchmarks (0-5)
Grok 4.5 (high)

Pricing Comparison

MetricGPT-5.6 Luna (max)Grok 4.5 (high)
Input ($/M tokens)$1$2
Output ($/M tokens)$6$6
Cost for 1M input + 100K output tokens:
GPT-5.6 Luna (max)$1.60
Grok 4.5 (high)$2.60

Speed Comparison

Output Speed (tokens/s) — higher is better
GPT-5.6 Luna (max)
264 tok/s
Grok 4.5 (high)
120 tok/s
Time to First Token (seconds) — lower is better
GPT-5.6 Luna (max)
45.96s
Grok 4.5 (high)
16.24s

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
51.253.8
Coding Index
71.472.4
Math Index
GPQA Diamond
91.1%93.1%
MMLU-Pro
LiveCodeBench
AIME 2025
MATH-500
Humanity's Last Exam
37.2%40.3%
SciCode
52.5%54.1%
IFBench
TerminalBench
GPT-5.6 Luna (max)0 wins
5 winsGrok 4.5 (high)

Frequently Asked Questions

Which is cheaper, GPT-5.6 Luna (max) or Grok 4.5 (high)?

GPT-5.6 Luna (max) is cheaper overall. Its blended price (3:1 input/output ratio) is $2.25/M tokens vs $3.00/M for Grok 4.5 (high).

Which model performs better on benchmarks?

Grok 4.5 (high) wins 5 out of 12 benchmarks compared to 0 for GPT-5.6 Luna (max). See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

GPT-5.6 Luna (max) generates tokens faster at 264 tok/s vs 120 tok/s. However, Grok 4.5 (high) has lower time-to-first-token (16.24s vs 45.96s).

When should I use GPT-5.6 Luna (max) vs Grok 4.5 (high)?

Choose based on your priorities: GPT-5.6 Luna (max) for lower cost, Grok 4.5 (high) for stronger benchmark performance, and GPT-5.6 Luna (max) for faster generation. For latency-sensitive apps, check the TTFT comparison above.