GPT-5.2 (xhigh) vs Claude Opus 4.5: Comprehensive Coding Comparison

The Current Landscape (December 2025)

GPT-5.2 lands in the middle of an arms race with Google’s Gemini 3, which is topping LMArena’s leaderboard across most benchmarks — apart from coding, which Anthropic’s Claude Opus 4.5 still has on lock.

Benchmark Head-to-Head

Claude Opus 4.5 achieved 80.9% on SWE-bench — the first model to break the 80% barrier.
GPT-5.2 Thinking scored 80% on SWE-bench Verified, essentially matching Opus 4.5’s performance.

Real Developer Experiences (From the Reddit Thread)

Pro-Claude Opinions:

• EatingDriving: “Claude and Claude Code in general is miles better than ChatGPT and Codex for numerous reasons. Claude is basically all code optimized.”
• Just_Lingonberry_352: “Opus 4.5 without question… beats 5.2 by a hundred points at least” on LM Arena. Notes that “5.2 is very slow” as the biggest complaint.
• FaithlessnessNo7800: “For my data engineering tasks, Claude Sonnet and Opus outperformed 5.2 without a doubt today.”

Pro-GPT-5.2 Opinions:

• Ok-Theme9419: “Fixed a complex data discrepancy bug 5.1 codex max and Opus 4.5 could not fix in one shot, very impressed so far.”
• Unique_Schedule_1627: “5.2 xhigh is the top model for me as of now, it seems to get the context right and implementation right every time.”
• lordpuddingcup: “Codex is back ahead… high is VERY VERY good”
• vuongagiflow: “It’s super good at tracing bugs.”

Key Differentiators

Where Claude Opus 4.5 Excels:

1. Claude Opus 4.5’s strength emerges most clearly in refactoring and debugging scenarios.
2. Claude Opus 4.5 is preferred for long-term projects requiring extended contextual analysis and autonomous operations.
3. Claude Opus 4.5 has a tendency to start writing code before it fully understands the problem — which can be a double-edged sword.
4. Speed: Multiple users report Opus is faster for quick questions and iterations.
5. Command-line proficiency: Leads on Terminal-Bench 2.0.

Where GPT-5.2 Excels:

1. Early testers found GPT-5.2 significantly stronger at front-end development and complex or unconventional UI work, making it a go-to choice for web developers working on interactive applications.
2. GPT-5.2 doesn’t just start coding. It asks questions. It reads files. It explores the codebase. It gathers context first, then writes code.
3. Abstract reasoning: Significantly better on ARC-AGI-2 benchmarks.
4. Math-heavy tasks: Perfect score on AIME 2025.
5. GPT-5.2 showed state of the art ability to use other software tools to complete tasks.

The Speed Problem

Standard GPT-5.2 Thinking is slow. In my experience it’s been very, very slow for most questions, even straightforward ones.

One Reddit user noted: “Claude was literally trash yesterday for me… extremely slow” — suggesting both models can have latency issues depending on load.

Language-Specific Performance

From the Reddit discussion:

• Swift: Mixed reports — some prefer Opus for one-shotting tasks, others found Codex better at edge cases
• Python/Rust/Golang: Da_ha3ker reported GPT-5.2 makes “much cleaner code” and proactively suggests type improvements
• TypeScript: mjakl found GPT consistently wins over Claude in their testing

Workflow Recommendations

For quick questions: the “what’s the syntax for X” or “remind me how Y works” type stuff, Claude Opus 4.5 wins. It’s faster and more to the point. For research tasks and complex reasoning, GPT-5.2 Pro is noticeably better.

One interesting workflow from TheAuthorBTLG_: “I use Opus for coding + Codex for reviews” — combining both models’ strengths.

Pricing Comparison

The API price for GPT 5.2 Pro is more than four times that of Claude Opus.

Bottom Line

Choose Claude Opus 4.5 if you:

• Do heavy refactoring and debugging work
• Need faster iteration cycles
• Work on long-horizon autonomous coding tasks
• Prefer a model that dives in quickly
• Use command-line/terminal workflows heavily

Choose GPT-5.2 (xhigh) if you:

• Build complex frontend/UI work
• Need strong mathematical reasoning in your code
• Want thorough context-gathering before code generation
• Work across multiple files/tools in complex workflows
• Don’t mind slower response times for better deliberation

The honest answer? They’re extremely close on core coding benchmarks (~80% SWE-bench for both). The Reddit consensus is that GPT-5.2 hasn’t created the same “magic moment” that Opus 4.5 did when it launched, but it’s a solid competitor. Many serious developers are now using both models — bouncing between them when one gets stuck, or using each for their strengths.