Compare/Claude Opus 4.8 (Adaptive Reasoning, Max Effort) vs gpt-oss-120b (high)

Claude Opus 4.8 (Adaptive Reasoning, Max Effort)vsgpt-oss-120b (high)

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

Anthropic

Claude Opus 4.8 (Adaptive Reasoning, Max Effort)

Input
$6.25/M
Output
$25/M
Speed
66 tok/s
TTFT
6.54s
OpenAI

gpt-oss-120b (high)

Input
$0.15/M
Output
$0.6/M
Speed
300 tok/s
TTFT
0.51s

Winner by Category

Cheaper
gpt-oss-120b (high)
Faster (tok/s)
gpt-oss-120b (high)
Lower Latency
gpt-oss-120b (high)
Benchmarks (6-5)
Claude Opus 4.8 (Adaptive Reasoning, Max Effort)

Pricing Comparison

MetricClaude Opus 4.8 (Adaptive Reasoning, Max Effort)gpt-oss-120b (high)
Input ($/M tokens)$6.25$0.15
Output ($/M tokens)$25$0.6
Cost for 1M input + 100K output tokens:
Claude Opus 4.8 (Adaptive Reasoning, Max Effort)$8.75
gpt-oss-120b (high)$0.21

Speed Comparison

Output Speed (tokens/s) — higher is better
Claude Opus 4.8 (Adaptive Reasoning, Max Effort)
66 tok/s
gpt-oss-120b (high)
300 tok/s
Time to First Token (seconds) — lower is better
Claude Opus 4.8 (Adaptive Reasoning, Max Effort)
6.54s
gpt-oss-120b (high)
0.51s

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
61.433.3
Coding Index
56.728.6
Math Index
93.4
GPQA Diamond
92.0%78.2%
MMLU-Pro
80.8%
LiveCodeBench
87.8%
AIME 2025
93.4%
MATH-500
Humanity's Last Exam
45.7%18.5%
SciCode
53.5%38.9%
IFBench
62.2%69.0%
TerminalBench
58.3%23.5%
Claude Opus 4.8 (Adaptive Reasoning, Max Effort)6 wins
5 winsgpt-oss-120b (high)

Frequently Asked Questions

Which is cheaper, Claude Opus 4.8 (Adaptive Reasoning, Max Effort) or gpt-oss-120b (high)?

gpt-oss-120b (high) is cheaper overall. Its blended price (3:1 input/output ratio) is $0.26/M tokens vs $10.94/M for Claude Opus 4.8 (Adaptive Reasoning, Max Effort).

Which model performs better on benchmarks?

Claude Opus 4.8 (Adaptive Reasoning, Max Effort) wins 6 out of 12 benchmarks compared to 5 for gpt-oss-120b (high). See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

gpt-oss-120b (high) generates tokens faster at 300 tok/s vs 66 tok/s. However, gpt-oss-120b (high) has lower time-to-first-token (0.51s vs 6.54s).

When should I use Claude Opus 4.8 (Adaptive Reasoning, Max Effort) vs gpt-oss-120b (high)?

Choose based on your priorities: gpt-oss-120b (high) for lower cost, Claude Opus 4.8 (Adaptive Reasoning, Max Effort) for stronger benchmark performance, and gpt-oss-120b (high) for faster generation. For latency-sensitive apps, check the TTFT comparison above.