Compare/Llama 3.1 Instruct 405B vs Grok 4.20 Beta 0309 (Reasoning)

Llama 3.1 Instruct 405BvsGrok 4.20 Beta 0309 (Reasoning)

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

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Llama 3.1 Instruct 405B

Input
$2.75/M
Output
$6.5/M
Speed
31 tok/s
TTFT
0.47s
xAI

Grok 4.20 Beta 0309 (Reasoning)

Input
$2/M
Output
$6/M
Speed
238 tok/s
TTFT
10.94s

Winner by Category

Cheaper
Grok 4.20 Beta 0309 (Reasoning)
Faster (tok/s)
Grok 4.20 Beta 0309 (Reasoning)
Lower Latency
Llama 3.1 Instruct 405B
Benchmarks (5-7)
Grok 4.20 Beta 0309 (Reasoning)

Pricing Comparison

MetricLlama 3.1 Instruct 405BGrok 4.20 Beta 0309 (Reasoning)
Input ($/M tokens)$2.75$2
Output ($/M tokens)$6.5$6
Cost for 1M input + 100K output tokens:
Llama 3.1 Instruct 405B$3.40
Grok 4.20 Beta 0309 (Reasoning)$2.60

Speed Comparison

Output Speed (tokens/s) — higher is better
Llama 3.1 Instruct 405B
31 tok/s
Grok 4.20 Beta 0309 (Reasoning)
238 tok/s
Time to First Token (seconds) — lower is better
Llama 3.1 Instruct 405B
0.47s
Grok 4.20 Beta 0309 (Reasoning)
10.94s

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
17.448.5
Coding Index
14.542.2
Math Index
3.0
GPQA Diamond
51.5%88.5%
MMLU-Pro
73.2%
LiveCodeBench
30.5%
AIME 2025
3.0%
MATH-500
70.3%
Humanity's Last Exam
4.2%30.0%
SciCode
29.9%44.7%
IFBench
39.0%82.9%
TerminalBench
6.8%40.9%
Llama 3.1 Instruct 405B5 wins
7 winsGrok 4.20 Beta 0309 (Reasoning)

Frequently Asked Questions

Which is cheaper, Llama 3.1 Instruct 405B or Grok 4.20 Beta 0309 (Reasoning)?

Grok 4.20 Beta 0309 (Reasoning) is cheaper overall. Its blended price (3:1 input/output ratio) is $3.00/M tokens vs $3.69/M for Llama 3.1 Instruct 405B.

Which model performs better on benchmarks?

Grok 4.20 Beta 0309 (Reasoning) wins 7 out of 12 benchmarks compared to 5 for Llama 3.1 Instruct 405B. See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

Grok 4.20 Beta 0309 (Reasoning) generates tokens faster at 238 tok/s vs 31 tok/s. Llama 3.1 Instruct 405B also has lower time-to-first-token (0.47s vs 10.94s).

When should I use Llama 3.1 Instruct 405B vs Grok 4.20 Beta 0309 (Reasoning)?

Choose based on your priorities: Grok 4.20 Beta 0309 (Reasoning) for lower cost, Grok 4.20 Beta 0309 (Reasoning) for stronger benchmark performance, and Grok 4.20 Beta 0309 (Reasoning) for faster generation. For latency-sensitive apps, check the TTFT comparison above.