The verdict

CPU
Lenovo ThinkCentre M70q Gen 1 has 1.8x the CPU throughput (10,221 vs 5,820 PassMark).
Plex
GMKtec NucBox G5 transcodes more 4K HDR streams (~5 vs ~3).
Idle power
GMKtec NucBox G5 idles lower (6W vs 10W) - cheaper to run 24/7.
RAM ceiling
Lenovo ThinkCentre M70q Gen 1 takes more RAM (64GB vs 12GB).
Local AI
Lenovo ThinkCentre M70q Gen 1 has a PCIe slot for a low-profile GPU - the other needs a DIY build for local LLMs.

Which wins for each job

Job GMKtec NucBox G5 Lenovo ThinkCentre M70q Gen 1
Plex / Jellyfin ~5 streams win ~3 streams
Frigate NVR ~4 cameras ~4 cameras
Proxmox / VMs 5,820 PassMark 10,221 PassMark win
Firewall / router 1 NICs 1 NICs
Local AI / LLM no slot PCIe GPU slot 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 GMKtec NucBox G5 Lenovo ThinkCentre M70q Gen 1
Price (list) $180 $175
CPU Intel Processor N97 Intel Core i5-10500T
Cores / threads 4 6
PassMark 5,820 10,221
iGPU Intel UHD UHD 630
NICs 1 1
NIC model Realtek RTL8111 Intel I219-V
RAM max (GB) 12 64
M.2 free 0 1
PCIe slot none x8-lp
Idle (W) 6 10
TDP (W) 12 35