Model Comparison
GLM-5.1 (Non-reasoning)
vs. GPT-4.5 (Preview)
Comparing 2 AI models · 7 benchmarks · Z AI, OpenAI
Recommended Pick
Op GPT-4.5 (Preview) 4 metric wins Strongest on: Input price, Output price, TTFT
Lowest Price
GPT-4.5 (Preview)
$0.00/1M input price
Best Reasoning
GLM-5.1 (Non-reasoning)
51.1 reasoning score
Blends available reasoning benchmarks
Best for Coding
GLM-5.1 (Non-reasoning)
35.8 coding index
Composite Indices
Higher is better; speed and price are normalized
Standard Benchmarks
Only benchmarks with data are shown
Differences That Matter
Price gap
GPT-4.5 (Preview) is ∞x cheaper on input tokens than GLM-5.1 (Non-reasoning).
Reasoning gap
GLM-5.1 (Non-reasoning) leads GPT-4.5 (Preview) by 31.1 points on reasoning.
Top-pick rationale
GPT-4.5 (Preview) wins 4 measurable categories, including Input price, Output price, TTFT, Latency.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
GLM-5.1 (Non-reasoning)
Z AI
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
GPT-4.5 (Preview)
OpenAI
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
Full Comparison
| Metric | Z GLM-5.1 (Non-reasoning) | Top Pick Op GPT-4.5 (Preview) |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $1.40/1M | $0.00/1M |
| Output Cost | $4.40/1M | $0.00/1M |
| Blended (3:1) | $2.15/1M | — |
| Specifications | ||
| Organization | Z AI | OpenAI |
| Release Date | Apr 7, 2026 | Feb 27, 2025 |
| Performance & Speed | ||
| Throughput | 66.7 tok/s | — |
| TTFT | 881ms | — |
| Latency | 881ms | — |
| Composite Indices | ||
| Value Score | 100.0 | — |
| Reasoning Score | 51.1 | 20.0 |
| Intelligence | 43.8 | 20.0 |
| Coding | 35.8 | — |
| Standard Benchmarks | ||
| GPQA | 83.9% | — |
| HLE | 25.6% | — |
| SciCode | 36.1% | — |
| LCR | 44.3% | — |
| IFBench | 52.0% | — |
| TAU-bench v2 | 97.1% | — |
| TerminalBench Hard | 35.6% | — |
Key Takeaways
GPT-4.5 (Preview) offers the best value at $0.00/1M, making it ideal for high-volume applications and cost-conscious projects.
GLM-5.1 (Non-reasoning) has the strongest reasoning profile with a 51.1 reasoning score, combining the available reasoning-heavy benchmarks.
GLM-5.1 (Non-reasoning) reaches a 35.8 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
GLM-5.1 (Non-reasoning)
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
GPT-4.5 (Preview)
- Cost-sensitive applications
- High-volume processing
