Which Llama model to pick
Rule of thumb: a model needs roughly 2x its parameter count in bytes of VRAM at FP16, or 1x at FP8/INT8. When in doubt, go one tier up — you can always downgrade later.
Option 1: Models API (easiest — no GPU needed)
The fastest path. Hit the Runcrate Models API directly and pay per token. No instance to manage, no vLLM to install, no GPU to provision.curl
Python (OpenAI SDK)
TypeScript (OpenAI SDK)
Option 2: Self-host with vLLM (full control)
Run your own OpenAI-compatible endpoint on a dedicated GPU. You control the model, the context length, the quantization, and the scaling.Deploy Llama 3.1 8B (single RTX 4090)
Deploy Llama 3.1 70B (single A100 80 GB)
Deploy Llama 4 Scout (single A100 80 GB)
Deploy Llama 3.1 405B FP8 (4x H100)
The 405B model requires tensor parallelism across multiple GPUs:Test your endpoint
Point your app at it
Once the server is running, point any OpenAI-compatible SDK at your instance:Monitoring
Option 3: Self-host with Ollama (simpler, quantized)
Ollama runs quantized models with a single command. Good for development and prototyping — not recommended for production throughput.Deploy and set up
Pull and serve a model
Test it
/v1/chat/completions, so you can use the same OpenAI SDK pattern:
Limitations
- Quantized models (Q4/Q5) trade quality for memory efficiency. For production accuracy, use vLLM with FP16 or FP8.
- Ollama’s serving throughput is lower than vLLM — fine for single-user development, not for concurrent production traffic.
- Larger models (70B Q4) need an A100 80 GB even with quantization.
Benchmarks
Expected throughput for each model/GPU combination with vLLM, batch size 1, 2048-token output:
Throughput scales with concurrent requests. At 8+ concurrent requests, vLLM’s continuous batching can push aggregate throughput 3–5x higher than single-request numbers.
Which approach to choose
Start with the Models API if you want to ship today. Move to vLLM self-hosting when you need dedicated throughput, custom context lengths, or want to keep all data on your own infrastructure.