GPT-5.5 vs GPT-5.4: What Changed and Is It Worth Upgrading?
Released on April 23, 2026, GPT-5.5 (codename "Spud") is the direct successor to GPT-5.4. OpenAI describes it as their "smartest and most intuitive to use model yet." But how much did things actually improve? Here's the complete GPT-5.5 vs GPT-5.4 comparison across every dimension that matters.
The Core Differences at a Glance
| Dimension | GPT-5.4 | GPT-5.5 |
|---|---|---|
| Release Date | Before April 2026 | April 23, 2026 |
| Context Window (API) | Large | 1,000,000 tokens |
| Context Window (Codex) | — | 400,000 tokens |
| Inference Speed | Baseline | Matches GPT-5.4 latency |
| Token Efficiency | Baseline | Fewer tokens for same tasks |
| API Input Price | — | $5 / 1M tokens |
| API Output Price | — | $30 / 1M tokens |
| Agentic Coding | Strong | Stronger |
| Computer Use | Good | Significantly better |
| Scientific Research | Capable | Major improvement |
Benchmark Comparison: GPT-5.5 vs GPT-5.4
OpenAI ran head-to-head benchmarks. Here are the key results:
Coding
| Benchmark | GPT-5.5 | GPT-5.4 | Δ Improvement |
|---|---|---|---|
| Terminal-Bench 2.0 | 82.7% | 75.1% | +7.6 pts |
| Expert-SWE (Internal) | 73.1% | 68.5% | +4.6 pts |
| SWE-Bench Pro | 58.6% | 57.7% | +0.9 pts |
Knowledge Work
| Benchmark | GPT-5.5 | GPT-5.4 |
|---|---|---|
| GDPval (wins/ties) | 84.9% | 83.0% |
| OSWorld-Verified | 78.7% | 75.0% |
| Tau2-bench Telecom | 98.0% | 92.8% |
| OfficeQA Pro | 54.1% | 53.2% |
| Investment Banking (Internal) | 88.5% | 87.3% |
Scientific Research
| Benchmark | GPT-5.5 | GPT-5.4 |
|---|---|---|
| GeneBench | 25.0% | 19.0% |
| BixBench | 80.5% | 74.0% |
| FrontierMath Tier 1–3 | 51.7% | 47.6% |
| FrontierMath Tier 4 | 35.4% | 27.1% |
Long Context
| Benchmark | GPT-5.5 | GPT-5.4 |
|---|---|---|
| MRCR 128K–256K | 87.5% | 79.3% |
| MRCR 256K–512K | 81.5% | 57.5% |
| MRCR 512K–1M | 74.0% | 36.6% |
The long-context improvements are dramatic — GPT-5.5 scores 74.0% on the 512K–1M range where GPT-5.4 scored only 36.6%.
Abstract Reasoning
| Benchmark | GPT-5.5 | GPT-5.4 |
|---|---|---|
| ARC-AGI-2 | 85.0% | 73.3% |
| ARC-AGI-1 | 95.0% | 93.7% |
The ARC-AGI-2 improvement (+11.7 points) is one of the most striking results of the release.
What Stayed the Same: Inference Speed
One of GPT-5.5's engineering achievements is matching GPT-5.4's per-token latency despite being a significantly more capable model. Serving GPT-5.5 required co-designing the model for NVIDIA GB200/GB300 NVL72 systems and rethinking inference as an integrated system.
One optimization alone — improved load balancing and partitioning heuristics developed with Codex assistance — increased token generation speeds by over 20%.
Token Efficiency: GPT-5.5 Uses Fewer Tokens
Even though GPT-5.5's output pricing is higher than GPT-5.4, it is more token-efficient: it completes the same tasks with fewer tokens and fewer retries. OpenAI specifically tuned the Codex experience so GPT-5.5 delivers better results with fewer tokens for most workflows.
Practical result: For Codex-heavy teams, GPT-5.5's higher per-token cost may be offset by lower total token consumption.
What GPT-5.5 Does Noticeably Better
1. Long-context reasoning. GPT-5.5 handles 512K–1M token contexts far better than GPT-5.4. This is the biggest practical improvement for large codebase analysis, long legal documents, and multi-document research.
2. Abstract reasoning. The ARC-AGI-2 jump (+11.7 points) reflects genuine improvements in novel problem-solving — not just benchmark optimization.
3. Scientific tasks. GeneBench improved by +6 points (from 19% to 25%). BixBench improved from 74% to 80.5%. GPT-5.5 is now described as a "bona fide co-scientist."
4. Autonomy in agentic tasks. Early testers described GPT-5.5 as "noticeably smarter and more persistent than GPT-5.4, staying on task for significantly longer without stopping early." (Michael Truell, Cursor CEO)
Should You Upgrade from GPT-5.4 to GPT-5.5?
API developers: Yes. Switch gpt-5.4 → gpt-5.5 in your model string. The long-context improvements alone justify it for most production workloads.
ChatGPT users: You already have access — GPT-5.5 is now the default model on Plus/Pro/Business/Enterprise plans.
Enterprise teams with Codex workflows: Yes — especially if your workflows involve large codebases, long documents, or research synthesis.
Cost-sensitive use cases: Run cost benchmarks on your specific workload. GPT-5.5 is more token-efficient, so the higher per-token price may not translate to higher total bills.
Using GPT-5.5 Through a Platform
If you want GPT-5.5's capabilities without managing API versions manually, Framia.pro provides AI workflows built on the latest OpenAI models. Framia.pro always runs on the current flagship model, so teams get GPT-5.5 performance for content, research, and automation tasks without configuration overhead.
Bottom Line
GPT-5.5 is a meaningful upgrade over GPT-5.4 — especially in long-context handling, abstract reasoning, and scientific research. It delivers these improvements at the same inference speed, with better token efficiency. For most production use cases, upgrading from GPT-5.4 to GPT-5.5 is a low-risk, high-reward decision.