Sixteen gigabytes is a practical starting point for local AI. Many 3B to 8B quantized models can work, but the exact file and context still matter.
Why 16 GB is a useful level
A 16 GB computer gives the operating system and AI model more room to work together. It can often run useful local assistants for writing, office work, private notes, and light coding.
This does not mean every 8B model will run well. Memory use changes with the model file, context length, engine, and other open programs.
Choose the model size by task
- Use 3B to 4B models when speed and low memory use matter most.
- Try 7B to 8B models when the task needs better instruction following or stronger writing.
- Choose a vision model only when the task includes images or screenshots.
- Use a coding model for repository and programming work.
- Use an embedding model plus a writing model for document search.
Do not spend all the memory
Leave several gigabytes for the operating system, the engine, and your normal apps. A long context also needs working memory beyond the downloaded file.
If the computer starts swapping memory to storage, answers can become very slow. A smaller model with a short context may feel much better than a larger model that barely fits.
The file, context, engine, and open apps all change memory use.
Compare two models fairly
- Use the same five to twenty real prompts.
- Use the same context length and answer length.
- Record first-word waiting time and total answer time.
- Score correctness and instruction following.
- Keep the smallest model that reaches your pass mark.
What to upgrade next
If quality is the main problem, test a stronger model before buying hardware. If speed is the problem, a supported GPU may help. If memory is always full, more RAM gives you room for larger files and longer contexts.
LocalLens separates these problems so a user does not buy a GPU when the real issue is model quality or poor task design.
Official references used
These primary sources support the technical concepts in this guide. Product behavior changes, so verify the current documentation before deployment.
Find a model your computer can run.
The LocalLens advisor applies conservative memory rules and tells you when the evidence is insufficient.
Run the free compatibility check →This guide is educational and reviewed for practical accuracy. Model software, licenses and hardware support change; verify official sources before a production deployment.