Grok 4 Fast Reasoning vs Llama 3.2 90B Instruct
Grok 4 Fast Reasoning (2025) and Llama 3.2 90B Instruct (2025) are frontier reasoning models from xAI and AI at Meta. Grok 4 Fast Reasoning ships a 2m-token context window, while Llama 3.2 90B Instruct ships a 128k-token context window. On pricing, Grok 4 Fast Reasoning costs $1.25/1M input tokens versus $1.35/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Grok 4 Fast Reasoning fits 16x more tokens; pick it for long-context work and Llama 3.2 90B Instruct for tighter calls.
Decision scorecard
Local evidence first| Signal | Grok 4 Fast Reasoning | Llama 3.2 90B Instruct |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and long-context analysis | multimodal apps |
| Decision fit | Long context and Vision | RAG, Long context, and Vision |
| Context window | 2m | 128k |
| Cheapest output | $2.50/1M tokens | $1.80/1M tokens |
| Provider routes | 2 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok 4 Fast Reasoning has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4 Fast Reasoning has broader tracked provider coverage for fallback and procurement flexibility.
- Grok 4 Fast Reasoning uniquely exposes Reasoning in local model data.
- Local decision data tags Grok 4 Fast Reasoning for Long context and Vision.
- Llama 3.2 90B Instruct has the lower cheapest tracked output price at $1.80/1M tokens.
- Llama 3.2 90B Instruct uniquely exposes Structured outputs in local model data.
- Local decision data tags Llama 3.2 90B Instruct for RAG, Long context, and Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Grok 4 Fast Reasoning
$1,625
Cheapest tracked route/tier: xAI Console
Llama 3.2 90B Instruct
$1,530
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $95.00. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for Grok 4 Fast Reasoning and Llama 3.2 90B Instruct; plan for SDK, billing, or endpoint changes.
- Llama 3.2 90B Instruct is $0.70/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning before moving production traffic.
- Llama 3.2 90B Instruct adds Structured outputs in local capability data.
- No overlapping tracked provider route is sourced for Llama 3.2 90B Instruct and Grok 4 Fast Reasoning; plan for SDK, billing, or endpoint changes.
- Grok 4 Fast Reasoning is $0.70/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Structured outputs before moving production traffic.
- Grok 4 Fast Reasoning adds Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-01 | 2025-09-01 |
| Context window | 2m | 128k |
| Parameters | — | 90B |
| Architecture | decoder only | - |
| License | Proprietary | Llama 3 Community |
| Openness | Proprietary | Open weights |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | 2023-12 |
Pricing and availability
| Pricing attribute | Grok 4 Fast Reasoning | Llama 3.2 90B Instruct |
|---|---|---|
| Input price | $1.25/1M tokens | $1.35/1M tokens |
| Output price | $2.50/1M tokens | $1.80/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4 Fast Reasoning | Llama 3.2 90B Instruct |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: Grok 4 Fast Reasoning and structured outputs: Llama 3.2 90B Instruct. Both models share vision and multimodal input, 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.
For cost, Grok 4 Fast Reasoning lists $1.25/1M input and $2.50/1M output tokens on the cheapest tracked provider, while Llama 3.2 90B Instruct lists $1.35/1M input and $1.80/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Llama 3.2 90B Instruct lower by about $0.14 per million blended tokens. Availability is 2 providers versus 1, so concentration risk also matters.
Choose Grok 4 Fast Reasoning when reasoning depth, larger context windows, and lower input-token cost are central to the workload. Choose Llama 3.2 90B Instruct when vision-heavy evaluation 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.
FAQ
Which has a larger context window, Grok 4 Fast Reasoning or Llama 3.2 90B Instruct?
Grok 4 Fast Reasoning supports 2m tokens, while Llama 3.2 90B Instruct supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Grok 4 Fast Reasoning or Llama 3.2 90B Instruct?
Llama 3.2 90B Instruct is cheaper on tracked token pricing. Grok 4 Fast Reasoning costs $1.25/1M input and $2.50/1M output tokens. Llama 3.2 90B Instruct costs $1.35/1M input and $1.80/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4 Fast Reasoning or Llama 3.2 90B Instruct open source?
Grok 4 Fast Reasoning is listed under Proprietary. Llama 3.2 90B Instruct is listed under Llama 3 Community. 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 vision, Grok 4 Fast Reasoning or Llama 3.2 90B Instruct?
Both Grok 4 Fast Reasoning and Llama 3.2 90B Instruct expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, Grok 4 Fast Reasoning or Llama 3.2 90B Instruct?
Both Grok 4 Fast Reasoning and Llama 3.2 90B Instruct expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Grok 4 Fast Reasoning and Llama 3.2 90B Instruct?
Grok 4 Fast Reasoning is available on Microsoft Foundry and xAI Console. Llama 3.2 90B Instruct is available on AWS Bedrock. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-04. Data sourced from public model cards and provider documentation.