GPT-5.4 vs Mistral Large 3

Choose GPT-5.4 if you want…

• ✓Higher intelligence (Artificial Analysis index 51)
• ✓Faster output (~144.2 tokens/sec)
• ✓Larger context window (1.1M)

Choose Mistral Large 3 if you want…

• ✓Lower price ($0.75 / 1M blended)

GPT-5.4

GPT-5.4 was built for the actual work that happens inside offices — financial modeling, legal analysis, complex codebases, and multi-step document workflows — rather than for chasing narrow benchmarks. That strategic shift shows in the numbers: it matched or outperformed human professionals in 83% of head-to-head comparisons, and developers have called its coding output "flawless," with some declaring it the definitive choice for complex software engineering work. Native computer-use capabilities let it operate browsers and desktop apps directly, and it scored above the human baseline on UI interaction tasks. The 1.05 million token context window handles large codebases and lengthy legal documents in a single pass, though you need to configure it explicitly — the default is 272K. Where GPT-5.4 falls short is nuance: it tends to interpret requests too literally, missing the intent behind ambiguous prompts in ways that Claude handles more naturally. Writing personality is another common frustration, with verbose follow-up suggestions that can feel mechanical. For structured professional tasks where thoroughness and tool integration matter more than prose feel, it is the strongest model in the GPT-5 line prior to the release of GPT-5.5.

Mistral Large 3

Mistral Large 3 is the French lab's flagship dense model, and on just4o.chat it runs through the Vercel AI Gateway under the mistral/mistral-large-3 route. It pairs strong general reasoning with the multilingual fluency Mistral is known for — European languages in particular — and reliable function calling for tool-driven workflows. A 256k-token context window is roomy enough for long documents, multi-file code, or extended chats without truncation, and at $0.50 per million input and $1.50 per million output tokens it sits at the affordable end of frontier-class models. On just4o.chat it is a base-tier model available on every plan, billed at 2 base requests per send before length multipliers. One practical note worth flagging up front: like the rest of the Mistral lineup here, it has no native web search, and it is text-only — no image input. For teams that want a capable, cost-disciplined generalist with first-rate multilingual handling, it is an easy default.