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Compare/Grok 3 Reasoning Beta vs Gemini 3.5 Flash (high)

Grok 3 Reasoning BetavsGemini 3.5 Flash (high)

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

SpaceXAI

Grok 3 Reasoning Beta

Input
—
Output
—
Speed
—
TTFT
—
Google

Gemini 3.5 Flash (high)

Input
$1.5/M
Output
$9/M
Speed
216 tok/s
TTFT
18.36s

Winner by Category

Cheaper
Gemini 3.5 Flash (high)
Faster (tok/s)
Gemini 3.5 Flash (high)
Lower Latency
Gemini 3.5 Flash (high)
Benchmarks (0-2)
Gemini 3.5 Flash (high)

Pricing Comparison

MetricGrok 3 Reasoning BetaGemini 3.5 Flash (high)
Input ($/M tokens)—$1.5
Output ($/M tokens)—$9
Cost for 1M input + 100K output tokens:
Gemini 3.5 Flash (high)$2.40

Speed Comparison

Output Speed (tokens/s) — higher is better
Grok 3 Reasoning Beta
—
Gemini 3.5 Flash (high)
216 tok/s
Time to First Token (seconds) — lower is better
Grok 3 Reasoning Beta
—
Gemini 3.5 Flash (high)
18.36s

Editorial Analysis

Verdict. Gemini 3.5 Flash (high) takes the aggregate benchmark matchup 2–0 across 2 categories. Real workloads usually care about a handful of specific tasks — see the per-benchmark table above.

Pricing. Pricing varies significantly between these models — check the table above for the exact per-token rates. Many production workloads actually surface input-token cost (retrieval-augmented prompts, code-context windows), so factor both directions.

Strengths. Grok 3 Reasoning Beta is strongest on Intelligence Index (10.4). Gemini 3.5 Flash (high) leads on Coding Index (70.1), Intelligence Index (33.0).

Speed. Speed data is incomplete for this pair; benchmark and price should decide.

Provider. SpaceXAI and Google sell to overlapping but distinct developer audiences: SpaceXAI tends to ship frontier reasoning models with premium positioning, while Google often prices more aggressively. Your existing vendor relationships, billing, and SLA preferences may matter as much as the raw numbers above.

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.

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
10.433.0
Coding Index
—70.1
Math Index
——
GPQA Diamond
——
MMLU-Pro
——
LiveCodeBench
——
AIME 2025
——
MATH-500
——
Humanity's Last Exam
——
SciCode
——
IFBench
——
TerminalBench
——
Grok 3 Reasoning Beta0 wins
2 winsGemini 3.5 Flash (high)

Frequently Asked Questions

Which is cheaper, Grok 3 Reasoning Beta or Gemini 3.5 Flash (high)?

Gemini 3.5 Flash (high) is cheaper overall. Its blended price (3:1 input/output ratio) is $3.38/M tokens vs $—/M for Grok 3 Reasoning Beta.

Which model performs better on benchmarks?

Gemini 3.5 Flash (high) wins 2 out of 12 benchmarks compared to 0 for Grok 3 Reasoning Beta. See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

Gemini 3.5 Flash (high) generates tokens faster at 216 tok/s vs — tok/s. However, Gemini 3.5 Flash (high) has lower time-to-first-token (18.36s vs —s).

When should I use Grok 3 Reasoning Beta vs Gemini 3.5 Flash (high)?

Choose based on your priorities: Gemini 3.5 Flash (high) for lower cost, Gemini 3.5 Flash (high) for stronger benchmark performance, and Gemini 3.5 Flash (high) for faster generation. For latency-sensitive apps, check the TTFT comparison above.