Why VRAM Is Everything
For gaming, you look at core count and clock speed. For local AI, there’s one spec that matters above all others: VRAM.
A language model needs to fit entirely in GPU memory to run at full speed. If it doesn’t fit, the model offloads to system RAM — and inference drops from 30+ tokens/second to 2-5 tokens/second. That’s the difference between a responsive assistant and a frustrating wait.
The formula: VRAM needed ≈ (parameters × bits) ÷ 8 + 1GB overhead
| Model Size | Q4 (4-bit) | Q8 (8-bit) | F16 (16-bit) |
|---|---|---|---|
| 3B | 2.5 GB | 4 GB | 7 GB |
| 7B | 5 GB | 8 GB | 15 GB |
| 13B | 8 GB | 14 GB | 27 GB |
| 30B | 18 GB | 32 GB | 62 GB |
| 70B | 42 GB | 75 GB | 145 GB |
Always target Q4 quantization for local use. The quality loss is negligible, and it halves your VRAM requirement compared to Q8.
Tier 1: Budget (6-8GB VRAM) — $150-250
RTX 3060 Ti 8GB ($150-200 used)
- Runs: 3B-7B models at full speed
- Tokens/sec: 30-50 t/s on 7B Q4
- Also handles: Stable Diffusion, basic ComfyUI workflows
- Verdict: Best budget card. We run one of these in our infrastructure — it handles image generation and 7B models without breaking a sweat.
RTX 4060 8GB ($200-250 new)
- Same VRAM as 3060 Ti, slightly faster cores
- Runs: Same models, slightly faster
- Verdict: Buy if you want new with warranty. Used 3060 Ti is better value.
RTX 2060 Super 8GB ($100-150 used)
- Older but still capable for 7B models
- Verdict: Budget emergency pick. Fine for testing, not for daily driver.
Tier 2: Mid-Range (10-12GB VRAM) — $250-400
RTX 3080 10GB ($250-350 used)
- Runs: 7B-9B models at full speed, 13B with slight offload
- Tokens/sec: 40-60 t/s on 7B Q4
- Verdict: Sweet spot for price/performance. We run a 3080 Ti 12GB in our LLM server.
RTX 3080 Ti 12GB ($300-400 used)
- Extra 2GB lets you run 9B models comfortably or 13B with minimal offload
- Verdict: If you find one under $350, grab it.
RTX 4070 12GB ($400-500 new)
- Same VRAM as 3080 Ti, newer architecture, lower power draw
- Verdict: Best new card in this tier. DLSS 3 support if you also game.
Tier 3: Enthusiast (16-24GB VRAM) — $500-900
RTX 3090 24GB ($700-900 used)
- Runs: 13B at full speed, 30B with partial offload
- Tokens/sec: 50-70 t/s on 13B Q4
- Also handles: Large ComfyUI workflows, LoRA training, multiple models simultaneously
- Verdict: The king of used AI GPUs. 24GB opens up 30B models and training. Power hungry (350W).
RTX 4090 24GB ($1500-1800 used)
- Same VRAM, 2x faster cores than 3090
- Verdict: If budget isn’t a concern. Most people don’t need this for local LLMs — the 3090 is 80% as good for half the price.
RTX 4080 Super 16GB ($900-1000 used)
- 16GB — enough for 13B with room for context
- Verdict: Good if you want newer architecture but can’t justify 4090 prices.
Tier 4: Multi-GPU (48GB+ VRAM) — $1400+
2× RTX 3090 (48GB total) ($1400-1800 used)
- Runs: 30B at full speed, 70B with partial offload
- Verdict: The budget AI workstation. Two 3090s in a single rig gives you 48GB for less than a single A100.
RTX A6000 48GB ($2000-3000 used)
- Single card, 48GB — no multi-GPU complexity
- Verdict: Professional workstation card. Overkill for most home users.
What About AMD?
AMD GPUs work with local AI but with caveats:
- ROCm support has improved dramatically in 2026
- Ollama supports AMD GPUs on Linux
- LM Studio added AMD support in 2026
- Performance: 10-20% slower than equivalent NVIDIA cards due to software maturity
- Best AMD picks: RX 7900 XTX 24GB ($700-900), RX 7800 XT 16GB ($450-550)
If you’re starting fresh, NVIDIA is still the path of least resistance. If you already own an AMD card, it’ll work — just expect more setup friction.
What About Apple Silicon?
Apple’s unified memory is a dark horse for local AI:
- M2/M3/M4 Ultra with 128GB+ unified RAM can run 70B models
- No VRAM split — the GPU can access all system memory
- LM Studio and Ollama both support Metal acceleration
- Performance: Slower than a 3090 for 7B models, but can run models that don’t fit on any consumer NVIDIA card
If you already own a high-RAM Mac, you have an AI machine. Don’t overlook it.
Our Recommendation by Budget
| Budget | Card | What You Get |
|---|---|---|
| $150 | Used 3060 Ti 8GB | 7B models, image gen |
| $300 | Used 3080 Ti 12GB | 9B-13B models, LoRA training |
| $800 | Used 3090 24GB | 30B models, multi-model, training |
| $1,500 | 2× Used 3090 | 70B models, serious workstation |
| $2,000+ | RTX 4090 24GB | Fastest single card, training beast |
Power Supply Matters
Don’t forget power. These cards draw serious wattage:
| Card | TDP | Min PSU |
|---|---|---|
| 3060 Ti | 200W | 550W |
| 3080 Ti | 350W | 750W |
| 3090 | 350W | 850W |
| 4090 | 450W | 1000W |
| 2× 3090 | 700W | 1200W |
Next Steps
- Run Your First Local AI Model in 15 Minutes — Get started with any GPU
- Run Local AI with No GPU — CPU-only options
- VRAM Calculator — Check what your card can run
Prices reflect the used market as of September 2026. Check eBay, r/hardwareswap, and Amazon Renewed for current deals.