The verdict

Plex
Nvidia Quadro T400 transcodes more streams (~24 vs ~18).
Local AI
Nvidia Tesla P4 has more VRAM (8GB vs 2GB) - up to ~8B (Q4).

Which wins for each job

Job Nvidia Quadro T400 Nvidia Tesla P4
Plex transcode ~24 streams win ~18 streams
Frigate NVR ~25 cameras ~25 cameras
Local LLM 2GB VRAM 8GB VRAM win
Fits a mini-PC low-profile PCIe low-profile PCIe

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 Quadro T400 Nvidia Tesla P4
Price (list) $130 $130
Type gpu gpu
Interface pcie pcie
Transcode H.264/HEVC (NVENC Turing) H.264/HEVC (NVENC Pascal)
Frigate detector TensorRT TensorRT
TOPS - -
VRAM (GB) 2 8
Low profile yes yes
GPU sharing vgpu (unlock) vgpu (unlock)
Power (W) 30 75