Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | Gemini 3.5 Flash-Lite | Grok 4.3 (medium) |
|---|---|---|
| Input ($/M tokens) | $0.3 | $1.25 |
| Output ($/M tokens) | $2.5 | $2.5 |
Verdict. Gemini 3.5 Flash-Lite wins the overall benchmark matchup 2–0 across 2 overlapping categories, but raw benchmark score is only one input to the decision.
Pricing. Both models sit in the budget bracket for output-token pricing. At 1.0× the per-million-token cost, Grok 4.3 (medium) is meaningfully cheaper if your traffic is output-heavy (long completions, document generation, agent loops). Grok 4.3 (medium) makes more sense when output volume is low and absolute reasoning quality justifies the premium.
Strengths. Gemini 3.5 Flash-Lite is strongest on Coding Index (49.3), Intelligence Index (37.4). Grok 4.3 (medium) leads on Intelligence Index (36.9).
Speed. On throughput, Gemini 3.5 Flash-Lite generates tokens at 391 tok/s versus 120 tok/s — about 69% faster. On time-to-first-token, Gemini 3.5 Flash-Lite responds in 6980ms vs 10770ms, which matters most for chat-style UIs.
Provider. Google and SpaceXAI sell to overlapping but distinct developer audiences: Google tends to ship frontier reasoning models with premium positioning, while SpaceXAI 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): Gemini 3.5 Flash-Lite costs $46.50 ($558/year); Grok 4.3 (medium) costs $75.00 ($900/year). At a smaller 5M-input/2M-output scale (single-developer tool or prototype): Gemini 3.5 Flash-Lite ≈ $6.50/run, Grok 4.3 (medium) ≈ $11.25/run. At agent/realtime scale (200M input / 100M output per million requests): Gemini 3.5 Flash-Lite ≈ $310/run, Grok 4.3 (medium) ≈ $500/run. Gemini 3.5 Flash-Lite 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
Gemini 3.5 Flash-Lite is cheaper overall. Its blended price (3:1 input/output ratio) is $0.85/M tokens vs $1.56/M for Grok 4.3 (medium).
Gemini 3.5 Flash-Lite wins 2 out of 12 benchmarks compared to 0 for Grok 4.3 (medium). See the detailed benchmark chart above for per-category results.
Gemini 3.5 Flash-Lite generates tokens faster at 391 tok/s vs 120 tok/s. Gemini 3.5 Flash-Lite also has lower time-to-first-token (6.98s vs 10.77s).
Choose based on your priorities: Gemini 3.5 Flash-Lite for lower cost, Gemini 3.5 Flash-Lite for stronger benchmark performance, and Gemini 3.5 Flash-Lite for faster generation. For latency-sensitive apps, check the TTFT comparison above.