Compare/GLM-5.1 (Reasoning) vs o4-mini (high)

GLM-5.1 (Reasoning)vso4-mini (high)

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

Z AI

GLM-5.1 (Reasoning)

Input
$1.4/M
Output
$4.4/M
Speed
79 tok/s
TTFT
1.08s
OpenAI

o4-mini (high)

Input
$1.1/M
Output
$4.4/M
Speed
128 tok/s
TTFT
32.11s

Winner by Category

Cheaper
o4-mini (high)
Faster (tok/s)
o4-mini (high)
Lower Latency
GLM-5.1 (Reasoning)
Benchmarks (6-6)
Tie

Pricing Comparison

MetricGLM-5.1 (Reasoning)o4-mini (high)
Input ($/M tokens)$1.4$1.1
Output ($/M tokens)$4.4$4.4
Cost for 1M input + 100K output tokens:
GLM-5.1 (Reasoning)$1.84
o4-mini (high)$1.54

Speed Comparison

Output Speed (tokens/s) — higher is better
GLM-5.1 (Reasoning)
79 tok/s
o4-mini (high)
128 tok/s
Time to First Token (seconds) — lower is better
GLM-5.1 (Reasoning)
1.08s
o4-mini (high)
32.11s

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
51.333.1
Coding Index
42.925.6
Math Index
90.7
GPQA Diamond
86.8%78.4%
MMLU-Pro
83.2%
LiveCodeBench
85.9%
AIME 2025
90.7%
MATH-500
98.9%
Humanity's Last Exam
28.0%17.5%
SciCode
43.8%46.5%
IFBench
76.3%68.7%
TerminalBench
42.4%15.2%
GLM-5.1 (Reasoning)6 wins
6 winso4-mini (high)

Frequently Asked Questions

Which is cheaper, GLM-5.1 (Reasoning) or o4-mini (high)?

o4-mini (high) is cheaper overall. Its blended price (3:1 input/output ratio) is $1.93/M tokens vs $2.15/M for GLM-5.1 (Reasoning).

Which model performs better on benchmarks?

It's a tie — both models win 6 benchmarks each across 12 evaluated categories. See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

o4-mini (high) generates tokens faster at 128 tok/s vs 79 tok/s. GLM-5.1 (Reasoning) also has lower time-to-first-token (1.08s vs 32.11s).

When should I use GLM-5.1 (Reasoning) vs o4-mini (high)?

Choose based on your priorities: o4-mini (high) for lower cost, both perform similarly on benchmarks, and o4-mini (high) for faster generation. For latency-sensitive apps, check the TTFT comparison above.