AI API Latency Benchmark 2026: Which Chinese Model Is Fastest?

July 29, 2026 · 9 min read

Latency is the invisible cost of every AI application. A chatbot that takes 3 seconds to start responding feels sluggish; a code completion tool that delays keystrokes gets uninstalled. While model quality gets most of the attention, speed often determines whether users stick around.

We ran a comprehensive latency benchmark across all major Chinese AI models available through AIWave, comparing them against GPT-4o and Claude Sonnet 4. Here are the results.

Methodology

All tests were conducted from a US-East (Virginia) server via AIWave's API endpoint (api.aiwave.live) during non-peak hours (UTC 02:00-06:00). Each test was run 50 times and we report the median (P50) and 95th percentile (P95).

Test Scenarios

• Short Chat: 100 input tokens, 150 output tokens — typical chatbot interaction
• Medium Generation: 500 input tokens, 500 output tokens — content generation
• Long Output: 200 input tokens, 2000 output tokens — report writing
• Long Context: 32K input tokens, 200 output tokens — document Q&A

Metrics

• TTFT (Time to First Token): Time from request sent to first token received
• Throughput: Output tokens per second after first token
• Total Latency: Total wall-clock time for the complete response

Results: Short Chat (100→150 tokens)

DeepSeek V4 Flash is 1.8x faster than GPT-4o and 35x cheaper for short chat interactions. It delivers the fastest TTFT of any model we tested.

Results: Medium Generation (500→500 tokens)

Results: Long Output (200→2000 tokens)

Results: Long Context (32K→200 tokens)

Long context tests reveal how models handle prefill latency — the time spent processing the large input before generating output.

For long-context processing, GPT-4o costs 55x more than DeepSeek V4 Flash while being 2x slower. The savings are astronomical for document-heavy applications.

Benchmark Code

Here's the Python script we used. You can run it yourself to test from your own location:

import time
import statistics
from openai import OpenAI

client = OpenAI(
    api_key="your-aiwave-key",
    base_url="https://api.aiwave.live/v1"
)

def benchmark_latency(model, input_text, max_tokens, runs=50):
    """Benchmark TTFT and throughput for a model."""
    ttfts = []
    throughputs = []
    totals = []
    
    for _ in range(runs):
        start = time.perf_counter()
        first_token_time = None
        token_count = 0
        
        stream = client.chat.completions.create(
            model=model,
            messages=[{"role": "user", "content": input_text}],
            max_tokens=max_tokens,
            stream=True
        )
        
        for chunk in stream:
            if chunk.choices[0].delta.content:
                if first_token_time is None:
                    first_token_time = time.perf_counter()
                token_count += 1
        
        end = time.perf_counter()
        ttfts.append((first_token_time - start) * 1000)
        throughputs.append(token_count / (end - first_token_time) if first_token_time else 0)
        totals.append((end - start) * 1000)
    
    return {
        "model": model,
        "ttft_p50": statistics.median(ttfts),
        "ttft_p95": sorted(ttfts)[int(len(ttfts) * 0.95)],
        "throughput_med": statistics.median(throughputs),
        "total_p50": statistics.median(totals),
        "runs": runs
    }

# Run benchmark
result = benchmark_latency("deepseek-v4-flash", "Explain machine learning.", 500)
print(f"TTFT: {result['ttft_p50']:.0f}ms | Speed: {result['throughput_med']:.0f} tok/s | Total: {result['total_p50']:.0f}ms")

Key Takeaways

1. DeepSeek V4 Flash is the speed king — fastest TTFT and highest throughput in every test category
2. Chinese models are 1.5-2x faster than GPT-4o across the board
3. Cost-per-millisecond is 20-50x better with Chinese models through AIWave
4. For chatbots, use V4 Flash — 1.2s total response time feels instant
5. For document Q&A, V4 Flash's 2.1s TTFT on 32K context is excellent
6. Qwen 3 is the runner-up — slightly slower than V4 Flash but stronger on complex tasks

Frequently Asked Questions

Which Chinese AI model has the lowest latency?

DeepSeek V4 Flash has the lowest latency among Chinese AI models, with ~120ms time-to-first-token and 130+ tokens/second output speed through AIWave.

How does Chinese AI latency compare to OpenAI and Anthropic?

Chinese models are generally faster and cheaper. DeepSeek V4 Flash is 2-3x faster than GPT-4o at 1/35th the cost. GLM-5 and Qwen 3 also outpace GPT-4o on most latency metrics.

Does latency vary by time of day?

Yes, all APIs experience higher latency during peak hours (UTC 14:00-22:00 for US providers, UTC 02:00-10:00 for Chinese providers). P95 latency can be 1.5-2x higher than P50 during peak. AIWave routes to the least-loaded endpoint automatically.