The verdict

Plex
Nvidia RTX A2000 12GB transcodes more streams (~24 vs ~12).
Local AI
Nvidia RTX A2000 12GB has more VRAM (12GB vs 8GB) - up to ~13B (Q4).
Fit
Nvidia RTX A2000 12GB is easier to add to a mini-PC (low-profile PCIe).

Which wins for each job

Job Nvidia RTX 3060 Ti Nvidia RTX A2000 12GB
Plex transcode ~12 streams ~24 streams win
Frigate NVR ~25 cameras ~25 cameras
Local LLM 8GB VRAM 12GB VRAM win
Fits a mini-PC full-size PCIe, DIY build low-profile PCIe win

Approximate - capacity estimates from curated specs, the same logic as the recommender. Verify against your exact setup. Prices move; check the retailer.

Full specs

Spec Nvidia RTX 3060 Ti Nvidia RTX A2000 12GB
Price (list) $330 $320
Type gpu gpu
Interface pcie pcie
Transcode H.264/HEVC (NVENC Ampere) H.264/HEVC (NVENC Ampere)
Frigate detector TensorRT TensorRT
TOPS - -
VRAM (GB) 8 12
Low profile no yes
GPU sharing - vgpu
Power (W) 200 70