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VRAM Budget & Model Sizing Guide

Formula for Q4_K_M

VRAM ≈ params_in_billions × 0.58 + context_vram (13 GB for 8K32K context)

Tight fit check: If a model loads but crashes on the first prompt, it's VRAM-starved. Drop one size tier.

Model Size Reference

Approximate VRAM at Q4_K_M (Ollama default):

Params Weight size Total VRAM Fits in
1B3B 0.61.8 GB 23 GB Any GPU
7B8B 45 GB 57 GB 6 GB+, comfortable on 8 GB
12B14B 79 GB 912 GB 11 GB+
22B24B 1214 GB 1417 GB 16 GB+
32B35B 1821 GB 2024 GB 24 GB
70B72B 3842 GB 4248 GB 48 GB+ or dual GPU

Quant Upsizing

Quant Multiplier 7B model 14B model 34B model
Q2_K ×0.33 2.3 GB 4.6 GB 11.2 GB
Q3_K_M ×0.40 2.8 GB 5.6 GB 13.6 GB
Q4_K_M ×0.58 4.1 GB 8.1 GB 19.7 GB
Q5_K_M ×0.68 4.8 GB 9.5 GB 23.1 GB
Q6_K ×0.80 5.6 GB 11.2 GB 27.2 GB
Q8_0 ×1.00 7.0 GB 14.0 GB 34.0 GB

Known-Good GPU Combos

GPU VRAM Best LLM (Q4_K_M) Best Vision
RTX 3060 12 GB qwen2.5:14b or mistral-nemo:12b llava:13b or llava-llama3:8b
RTX 2080 Ti 11 GB qwen2.5:14b (tight) or mistral-nemo:12b llava:13b (tight) or llava-llama3:8b
RTX 3090 24 GB qwen2.5:32b or llama3:70b (Q3) llava:34b or llama3.2-vision:11b
RTX 4090 24 GB Same as 3090 Same
RTX 4070 12 GB Same as 3060 Same

Ollama GPU Investigation

When the user asks "what's using my GPU":

  1. nvidia-smi — all GPU processes with PIDs and VRAM usage
  2. ps -p <PID> -o pid,args --no-headers — which model and port each process runs
  3. curl -s http://localhost:11434/api/ps | python3 -m json.tool — Ollama model details, quant, expiry
  4. journalctl -u ollama --since "5 min ago" --no-pager — recent Ollama activity

The expires_at field tells when Ollama auto-unloads (default 5 min idle).

Removing Stale llama.cpp Server

kill <PID>
rm -rf /path/to/build /path/to/model.gguf
sudo systemctl stop llama-server 2>/dev/null
sudo systemctl disable llama-server 2>/dev/null
sudo rm /etc/systemd/system/llama-server.service
sudo systemctl daemon-reload