The verdict

Plex
Nvidia RTX 4000 SFF Ada transcodes more streams (~45 vs ~12).
Local AI
Nvidia RTX PRO 4000 Blackwell SFF has more VRAM (24GB vs 20GB) - up to ~33B (Q4).

Which wins for each job

Job Nvidia RTX 4000 SFF Ada Nvidia RTX PRO 4000 Blackwell SFF
Plex transcode ~45 streams win ~12 streams
Frigate NVR ~25 cameras ~25 cameras
Local LLM 20GB VRAM 24GB 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 RTX 4000 SFF Ada Nvidia RTX PRO 4000 Blackwell SFF
Price (list) $1,250 $1,500
Type gpu gpu
Interface pcie pcie
Transcode H.264/HEVC/AV1 encode (NVENC Ada) H.264/HEVC/AV1 (NVENC Blackwell 4:2:2)
Frigate detector TensorRT TensorRT
TOPS - -
VRAM (GB) 20 24
Low profile yes yes
GPU sharing vgpu vgpu
Power (W) 70 70