Grok 4 Heavy vs Phi-3 Mini 4k
Grok 4 Heavy (2025) and Phi-3 Mini 4k (2024) are compact production models from xAI and Microsoft Research. Grok 4 Heavy ships a 256k-token context window, while Phi-3 Mini 4k ships a 4K-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
Grok 4 Heavy fits 64x more tokens; pick it for long-context work and Phi-3 Mini 4k for tighter calls.
Specs
| Released | 2025-07-09 | 2024-04-23 |
| Context window | 256k | 4K |
| Parameters | — | 3.8B |
| Architecture | - | decoder only |
| License | Proprietary | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Grok 4 Heavy | Phi-3 Mini 4k | |
|---|---|---|
| Input price | - | $0.05/1M tokens |
| Output price | - | $0.25/1M tokens |
| Providers | - |
Capabilities
| Grok 4 Heavy | Phi-3 Mini 4k | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on multimodal input: Grok 4 Heavy. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: Grok 4 Heavy has no token price sourced yet and Phi-3 Mini 4k has $0.05/1M input tokens. Provider availability is 0 tracked routes versus 4. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Grok 4 Heavy when long-context analysis and larger context windows are central to the workload. Choose Phi-3 Mini 4k when provider fit and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency. For teams standardizing a stack, that distinction is often the difference between a benchmark win and a reliable deployment.
FAQ
Which has a larger context window, Grok 4 Heavy or Phi-3 Mini 4k?
Grok 4 Heavy supports 256k tokens, while Phi-3 Mini 4k supports 4K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Grok 4 Heavy or Phi-3 Mini 4k open source?
Grok 4 Heavy is listed under Proprietary. Phi-3 Mini 4k is listed under Open Source. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for multimodal input, Grok 4 Heavy or Phi-3 Mini 4k?
Grok 4 Heavy has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Grok 4 Heavy and Phi-3 Mini 4k?
Grok 4 Heavy is available on the tracked providers still being sourced. Phi-3 Mini 4k is available on Microsoft Foundry, NVIDIA NIM, Baseten API, and Replicate API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Grok 4 Heavy over Phi-3 Mini 4k?
Grok 4 Heavy fits 64x more tokens; pick it for long-context work and Phi-3 Mini 4k for tighter calls. If your workload also depends on long-context analysis, start with Grok 4 Heavy; if it depends on provider fit, run the same evaluation with Phi-3 Mini 4k.
Continue comparing
Last reviewed: 2026-04-18. Data sourced from public model cards and provider documentation.