Compare/Phi-4 vs Grok 4.1 Fast (Reasoning)

Phi-4vsGrok 4.1 Fast (Reasoning)

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

Microsoft Azure

Phi-4

Input
$0.125/M
Output
$0.5/M
Speed
37 tok/s
TTFT
0.41s
xAI

Grok 4.1 Fast (Reasoning)

Input
$0.2/M
Output
$0.5/M
Speed
139 tok/s
TTFT
8.22s

Winner by Category

Cheaper
Phi-4
Faster (tok/s)
Grok 4.1 Fast (Reasoning)
Lower Latency
Phi-4
Benchmarks (1-11)
Grok 4.1 Fast (Reasoning)

Pricing Comparison

MetricPhi-4Grok 4.1 Fast (Reasoning)
Input ($/M tokens)$0.125$0.2
Output ($/M tokens)$0.5$0.5
Cost for 1M input + 100K output tokens:
Phi-4$0.17
Grok 4.1 Fast (Reasoning)$0.25

Speed Comparison

Output Speed (tokens/s) — higher is better
Phi-4
37 tok/s
Grok 4.1 Fast (Reasoning)
139 tok/s
Time to First Token (seconds) — lower is better
Phi-4
0.41s
Grok 4.1 Fast (Reasoning)
8.22s

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
10.438.6
Coding Index
11.230.9
Math Index
18.089.3
GPQA Diamond
57.5%85.3%
MMLU-Pro
71.4%85.4%
LiveCodeBench
23.1%82.2%
AIME 2025
18.0%89.3%
MATH-500
81.0%
Humanity's Last Exam
4.1%17.6%
SciCode
26.0%44.2%
IFBench
23.5%52.7%
TerminalBench
3.8%24.2%
Phi-41 wins
11 winsGrok 4.1 Fast (Reasoning)

Frequently Asked Questions

Which is cheaper, Phi-4 or Grok 4.1 Fast (Reasoning)?

Phi-4 is cheaper overall. Its blended price (3:1 input/output ratio) is $0.22/M tokens vs $0.28/M for Grok 4.1 Fast (Reasoning).

Which model performs better on benchmarks?

Grok 4.1 Fast (Reasoning) wins 11 out of 12 benchmarks compared to 1 for Phi-4. See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

Grok 4.1 Fast (Reasoning) generates tokens faster at 139 tok/s vs 37 tok/s. Phi-4 also has lower time-to-first-token (0.41s vs 8.22s).

When should I use Phi-4 vs Grok 4.1 Fast (Reasoning)?

Choose based on your priorities: Phi-4 for lower cost, Grok 4.1 Fast (Reasoning) for stronger benchmark performance, and Grok 4.1 Fast (Reasoning) for faster generation. For latency-sensitive apps, check the TTFT comparison above.