Model comparison
GPT-5.3-Codex-Spark vs o3-pro
Head-to-head evidence from 0 shared benchmark results across 0 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.3-Codex-Spark #73 (Estimated); o3-pro #127 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.3-Codex-Spark and o3-pro share 0 comparable benchmark results. 0 of 8 categories are comparable. 0 results are unique to GPT-5.3-Codex-Spark; 2 to o3-pro.
Updated July 18, 2026- Shared results
- 0
- GPT-5.3-Codex-Spark only
- 0
- o3-pro only
- 2
- Comparable categories
- 0 / 8
Benchmark data for GPT-5.3-Codex-Spark and o3-pro is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 0 shared benchmark results across 0 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM does not have sourced benchmark coverage for GPT-5.3-Codex-Spark yet. This comparison is currently limited to metadata such as context window, reasoning mode, and pricing where available.
GPT-5.3-Codex-Spark has the larger context window at 256K, compared with 200K for o3-pro.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.3-Codex-Spark | o3-pro | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.3-Codex-SparkNot available | o3-pro$20 input / $80 output | A complete price comparison is not available. |
| Generation speedtokens per second | GPT-5.3-Codex-SparkNot available | o3-pro27 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.3-Codex-SparkNot available | o3-pro84.93 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.3-Codex-Spark256K | o3-pro200K | GPT-5.3-Codex-Spark lists the larger context window. |
Benchmark Deep Dive
Frequently Asked Questions (3)
Can I compare GPT-5.3-Codex-Spark and o3-pro on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for GPT-5.3-Codex-Spark and o3-pro today?
GPT-5.3-Codex-Spark: Pricing unavailable o3-pro: $20.00 input / $80.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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