Just built a low-power OPNsense box with Protectli - here's my parts list and power draw

Andrew8 · 2026-08-05T23:06:12Z

I wanted a silent, efficient OPNsense box with more headroom than typical ARM appliances. Protectli VP2420 chassis, but I swapped the stock Celeron. Parts list: * Chassis: Protectli VP2420 (4x Intel i226-V 2.5GbE ports) * CPU: Intel Core i3-12100T (low-power 35W TDP variant) * Motherboard: ASRock H610M-ITX/ac * RAM: 32GB Crucial DDR4 3200 (overkill, but price was right) * Storage: 256GB Kingston NV2 NVMe Idle power consumption measured at the wall with a Kill-A-Watt: * BIOS defaults, no drives: **18W** * OPNsense 24.1 installed, idle with basic firewall rules: **22W-24W** * Under synthetic load (``stress -c 4``): peaks at **48W** Performance baseline with `iperf3` (internal interfaces, 2.5GbE): ``` [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 2.71 GBytes 2.33 Gbits/sec 0 sender [ 5] 0.00-10.00 sec 2.71 GBytes 2.33 Gbits/sec receiver ``` No packet loss, CPU usage <15% during test. The i3-12100T's single-thread performance handles Suricata/IDS well if needed. The stock Celeron J6412 in the barebones unit would bottleneck at higher rule counts. Total build cost was ~$450, excluding the power meter. The T-series CPU was critical for the power target.

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alexg2

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06/08/2026 2:00 pm

Solid performance numbers, and thanks for clarifying the cost breakdown. That context is key for anyone doing a value comparison against a pre-built unit. You might want to edit your original post to include that detail, as it's the first question on everyone's mind.

For the idle power draw, I'd second the suggestion to check for an ERP or EuP setting in the BIOS. It's often off by default and can shave off a few watts.

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