Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | GPT-5.4 (xhigh) | Kimi K3 (low) |
|---|---|---|
| Input ($/M tokens) | $2.5 | $3 |
| Output ($/M tokens) | $15 | $15 |
Verdict. GPT-5.4 (xhigh) and Kimi K3 (low) split the benchmark comparison evenly at 1–1. The tiebreaker here is price, speed, and what you actually run them on.
Pricing. Both models sit in the premium bracket for output-token pricing. At 1.0× the per-million-token cost, Kimi K3 (low) is meaningfully cheaper if your traffic is output-heavy (long completions, document generation, agent loops). Kimi K3 (low) makes more sense when output volume is low and absolute reasoning quality justifies the premium.
Strengths. GPT-5.4 (xhigh) is strongest on Coding Index (71.1), Intelligence Index (53.1). Kimi K3 (low) leads on Coding Index (72.0), Intelligence Index (48.3).
Speed. On throughput, GPT-5.4 (xhigh) generates tokens at 131 tok/s versus 36 tok/s — about 72% faster. On time-to-first-token, Kimi K3 (low) responds in 2820ms vs 144080ms, which matters most for chat-style UIs.
Provider. OpenAI and Kimi sell to overlapping but distinct developer audiences: OpenAI tends to ship frontier reasoning models with premium positioning, while Kimi often prices more aggressively. Your existing vendor relationships, billing, and SLA preferences may matter as much as the raw numbers above.
Workload cost. Workload scenarios (per million requests at 30M input + 15M output tokens): GPT-5.4 (xhigh) costs $300.00 ($3600/year); Kimi K3 (low) costs $315.00 ($3780/year). At a smaller 5M-input/2M-output scale (single-developer tool or prototype): GPT-5.4 (xhigh) ≈ $42.50/run, Kimi K3 (low) ≈ $45.00/run. At agent/realtime scale (200M input / 100M output per million requests): GPT-5.4 (xhigh) ≈ $2000/run, Kimi K3 (low) ≈ $2100/run. GPT-5.4 (xhigh) becomes more attractive at higher volume — the absolute per-token pricing difference compounds when you ship at scale.
Recommendation. Both models have legitimate use cases — the right answer depends on whether you are optimizing for benchmark ceiling, latency, or unit cost. Start with the cheaper / faster model, evaluate against your specific task, and only switch if the upgrade shows a meaningful lift.
Head-to-head deltas
Data from Artificial Analysis API — 12 benchmarks
GPT-5.4 (xhigh) is cheaper overall. Its blended price (3:1 input/output ratio) is $5.63/M tokens vs $6.00/M for Kimi K3 (low).
It's a tie — both models win 1 benchmarks each across 12 evaluated categories. See the detailed benchmark chart above for per-category results.
GPT-5.4 (xhigh) generates tokens faster at 131 tok/s vs 36 tok/s. However, Kimi K3 (low) has lower time-to-first-token (2.82s vs 144.08s).
Choose based on your priorities: GPT-5.4 (xhigh) for lower cost, both perform similarly on benchmarks, and GPT-5.4 (xhigh) for faster generation. For latency-sensitive apps, check the TTFT comparison above.