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 SizeQ4 (4-bit)Q8 (8-bit)F16 (16-bit)
3B2.5 GB4 GB7 GB
7B5 GB8 GB15 GB
13B8 GB14 GB27 GB
30B18 GB32 GB62 GB
70B42 GB75 GB145 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

BudgetCardWhat You Get
$150Used 3060 Ti 8GB7B models, image gen
$300Used 3080 Ti 12GB9B-13B models, LoRA training
$800Used 3090 24GB30B models, multi-model, training
$1,5002× Used 309070B models, serious workstation
$2,000+RTX 4090 24GBFastest single card, training beast

Power Supply Matters

Don’t forget power. These cards draw serious wattage:

CardTDPMin PSU
3060 Ti200W550W
3080 Ti350W750W
3090350W850W
4090450W1000W
2× 3090700W1200W

Next Steps


Prices reflect the used market as of September 2026. Check eBay, r/hardwareswap, and Amazon Renewed for current deals.