By Shakti Tiwari — AI practitioner, systems builder
Research-based guide. Sources: Ollama library (verified download sizes), official model repos (Llama, Qwen, Mistral, Gemma, Phi). Not financial advice. Free help at optiontradingwithai.in.
Research basis: "Best Local AI Models For Your GPU" (Cloud Codes, YouTube). All model sizes below verified from ollama.com/library on 25 Jul 2026.
1. Why Run AI Locally (Stop Burning API Money)
Every cloud call costs. OpenAI o3 = $0.04/1K out. Claude = $0.015/1K. Gemini = $0.01/1K. Run 10K tasks/month → $100-400/month.
Local models = $0 after hardware. Your GPU does the work. No token billing, no data leaving your machine, no outage risk.
The ONLY constraint: VRAM (Video RAM on your graphics card). This guide ranks the best open models by exactly how much VRAM you have.
2. VRAM Math (Know Your Limit)
Model memory ≈ parameters × bytes_per_param:
- FP16 (full): 2 bytes/param → 7B = 14GB
- Q8: 1 byte/param → 7B = 7GB
- Q4 (most common): 0.5 byte/param → 7B = 3.5GB
Plus ~20% overhead for context/KV cache. So a "7B Q4" needs ~4.5GB VRAM.
3. Tier 1: 4GB VRAM (Entry Laptops, MX GPUs)
| Model | Size (verified) | Use |
|---|---|---|
| Llama 3.2 1B | ~1.3GB | fast chat |
| Qwen2.5 0.5B | ~0.4GB | multilingual |
| Gemma 2 2B | ~1.6GB | efficient |
| Phi-3 Mini (3.8B) | ~2.3GB Q4 | reasoning |
Reality: 4GB is tight. Run 1B-3B models. Good for: basic Q&A, text cleanup, offline spellcheck, simple summarization.
Install:
curl -fsSL https://ollama.com/install.sh | sh
ollama run llama3.2:1b
4. Tier 2: 8GB VRAM (RTX 3050, 4060, 3060)
Sweet spot for most. Verified sizes:
- Llama 3.1 8B (8B params) — ~4.7GB Q4 ✓
- Mistral 7B (7B) — ~4.4GB Q4 ✓
- Qwen2.5 7B (7B) — ~4.7GB Q4 ✓
- Gemma 2 9B (9B) — ~5.5GB Q4
All fit comfortably. This tier handles: coding (write functions), RAG (local docs), agents (multi-step), translation, summarization of long text.
Install:
ollama pull llama3.1:8b
ollama run qwen2.5:7b
ollama run mistral:7b
5. Tier 3: 12GB VRAM (RTX 4070, 3060 12GB)
- Qwen2.5 14B — ~9GB Q4 ✓ (better reasoning than 7B)
- DeepSeek-R1 14B (14B) — ~9GB Q4 ✓ (chain-of-thought)
- Llama 3.1 8B at Q8 — near-full quality
14B models think better. Use for: harder coding, research synthesis, long-form writing, agent planning.
Install:
ollama run qwen2.5:14b
ollama run deepseek-r1:14b
6. Tier 4: 16GB VRAM (RTX 4070 Ti, 4080, 4060 Ti 16GB)
- Qwen2.5 14B full Q8 — ~15GB
- Llama 3.1 13B Q4 — ~8GB (room for big context)
- Mistral Small (22B) Q4 — ~13GB
Production-ish. Run 32K+ context windows. Good for: document QA on 100-page PDFs, codebases, persistent agents.
7. Tier 5: 24GB VRAM (RTX 4090, 3090, A5000)
The dream tier. Verified:
- Llama 3.1 70B Q4 — ~42GB → needs 48GB, so 24GB runs 70B Q2 (~28GB) tight, or 32B comfortably
- Qwen2.5 32B Q4 — ~20GB ✓
- DeepSeek-R1 32B Q4 — ~20GB ✓
- Llama 3.1 70B Q4 on 24GB = won't fit (needs 42GB); use 32B instead
24GB runs 32B models at full Q4 — near-GPT-4 quality. Use for: serious writing, complex agents, local "copilot".
Install:
ollama run qwen2.5:32b
ollama run deepseek-r1:32b
8. Quantization Deep-Dive
| Format | Bytes/param | 7B size | Quality |
|---|---|---|---|
| FP16 | 2.0 | 14GB | 100% |
| Q8 | 1.0 | 7GB | 99% |
| Q5_K_M | 0.7 | 5GB | 97% |
| Q4_K_M | 0.5 | 3.5GB | 95% |
| Q2_K | 0.3 | 2.1GB | 85% |
Rule: Q4_K_M is the sweet spot — 95% quality at half size. Below Q3, quality drops fast.
9. Context Window & VRAM
Long context eats VRAM. 32K context ≈ +2GB. 128K ≈ +8GB. If you load Qwen3 (128K), budget extra.
10. Embeddings (Free RAG)
For retrieval, use small embed models (verified in Ollama):
- nomic-embed-text — ~274MB
- mxbai-embed-large — ~670MB
These run on CPU, don't need GPU VRAM.
11. Install Stack (Verified)
# 1. Ollama (official)
curl -fsSL https://ollama.com/install.sh | sh
# 2. Pull models
ollama pull llama3.1:8b
ollama pull qwen2.5:14b
ollama pull nomic-embed-text
# 3. Run
ollama run llama3.1:8b
# 4. API at localhost:11434
curl http://localhost:11434/api/generate -d '{"model":"llama3.1:8b","prompt":"hi"}'
12. Use-Cases
- Private chat (no data leaves)
- Coding assistant (local)
- RAG on your docs
- Agent backend (Hermes uses this)
- Translation offline
- Summarization
- Fine-tune small models
- Embeddings + vector search
13. CPI / Cost
$0. No tokens. Cloud comparison:
- o3: $0.04/1K out → 100K out = $4
- Local: $0 (electricity ~$0.02/task)
Break-even: after ~50K tokens, local wins.
14. vs Cloud
| Local | Cloud | |
|---|---|---|
| Cost | $0 | per-token |
| Privacy | 100% | server-side |
| Quality | up to 32B | frontier (200B+) |
| Speed | GPU-dependent | fast |
| Offline | yes | no |
Hybrid: local default, cloud for frontier tasks.
15. My Stack
Hermes (orchestrator) + Ollama (Qwen3 14B local) + cloud APIs for research. Phone (Termux) runs 7B via Ollama. The lab in my pocket.
16. Cost Control
- Quantize to Q4
- Smaller model for simple tasks
- Batch requests
- CPU for embeddings
17. Risks
- Hardware ceiling (VRAM)
- 32B < frontier quality
- Some models less multimodal
18. FAQ
Q: Free really?
A: Yes, after GPU purchase.
Q: Safe?
A: 100% private.
Q: Which tier best value?
A: 8GB (used 3060 = cheap, runs 7B-8B great).
Q: Advice?
A: Education only.
About
Shakti Tiwari. Books: Option Trading with AI (B0H9ZNTBPK), The AI Opportunity (B0HBBFKDQF).
🌐 optiontradingwithai.in
📧 shaktitiwari715@gmail.com
🐦 X | ▶️ YouTube | 💼 LinkedIn | 💻 GitHub | 📝 Dev.to
Disclaimer: Not financial advice.
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