Compare/Gemini 2.5 Flash Preview (Sep '25) (Reasoning) vs gpt-oss-20b (high)

Gemini 2.5 Flash Preview (Sep '25) (Reasoning)vsgpt-oss-20b (high)

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

Google

Gemini 2.5 Flash Preview (Sep '25) (Reasoning)

Input
$0/M
Output
$0/M
Speed
TTFT
OpenAI

gpt-oss-20b (high)

Input
$0.05/M
Output
$0.2/M
Speed
185 tok/s
TTFT
0.48s

Winner by Category

Cheaper
Gemini 2.5 Flash Preview (Sep '25) (Reasoning)
Faster (tok/s)
gpt-oss-20b (high)
Lower Latency
Gemini 2.5 Flash Preview (Sep '25) (Reasoning)
Benchmarks (6-5)
Gemini 2.5 Flash Preview (Sep '25) (Reasoning)

Pricing Comparison

MetricGemini 2.5 Flash Preview (Sep '25) (Reasoning)gpt-oss-20b (high)
Input ($/M tokens)$0$0.05
Output ($/M tokens)$0$0.2
Cost for 1M input + 100K output tokens:
Gemini 2.5 Flash Preview (Sep '25) (Reasoning)$0.00
gpt-oss-20b (high)$0.07

Speed Comparison

Output Speed (tokens/s) — higher is better
Gemini 2.5 Flash Preview (Sep '25) (Reasoning)
gpt-oss-20b (high)
185 tok/s
Time to First Token (seconds) — lower is better
Gemini 2.5 Flash Preview (Sep '25) (Reasoning)
gpt-oss-20b (high)
0.48s

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
23.814.9
Coding Index
20.7
Math Index
78.389.3
GPQA Diamond
79.3%68.8%
MMLU-Pro
84.2%74.8%
LiveCodeBench
71.3%77.7%
AIME 2025
78.3%89.3%
MATH-500
Humanity's Last Exam
12.7%9.8%
SciCode
40.5%34.4%
IFBench
52.3%65.1%
TerminalBench
16.7%10.6%
Gemini 2.5 Flash Preview (Sep '25) (Reasoning)6 wins
5 winsgpt-oss-20b (high)

Frequently Asked Questions

Which is cheaper, Gemini 2.5 Flash Preview (Sep '25) (Reasoning) or gpt-oss-20b (high)?

Gemini 2.5 Flash Preview (Sep '25) (Reasoning) is cheaper overall. Its blended price (3:1 input/output ratio) is $0.00/M tokens vs $0.09/M for gpt-oss-20b (high).

Which model performs better on benchmarks?

Gemini 2.5 Flash Preview (Sep '25) (Reasoning) wins 6 out of 12 benchmarks compared to 5 for gpt-oss-20b (high). See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

gpt-oss-20b (high) generates tokens faster at 185 tok/s vs 0 tok/s. Gemini 2.5 Flash Preview (Sep '25) (Reasoning) also has lower time-to-first-token (0.00s vs 0.48s).

When should I use Gemini 2.5 Flash Preview (Sep '25) (Reasoning) vs gpt-oss-20b (high)?

Choose based on your priorities: Gemini 2.5 Flash Preview (Sep '25) (Reasoning) for lower cost, Gemini 2.5 Flash Preview (Sep '25) (Reasoning) for stronger benchmark performance, and gpt-oss-20b (high) for faster generation. For latency-sensitive apps, check the TTFT comparison above.