OPNsense Hardware Requirements: CPU, RAM, Storage & NICs
Quick Answer: What Hardware Does OPNsense Need?
For a new OPNsense firewall, start with a 64-bit x86 system, a multi-core CPU, 8 GB RAM, an SSD, and network interfaces supported by the OPNsense release you plan to install. OPNsense's official recommended specification is a 1.5 GHz multi-core CPU, 8 GB RAM, and a 120 GB SSD. Its minimum specification is lower, but does not cover every disk-writing feature.
Those figures describe a software baseline, not a guarantee of routing, VPN, or IDS/IPS throughput. Choose hardware based on WAN speed, firewall features, concurrent connections, network ports, and whether OPNsense runs on dedicated hardware or a virtual machine.
- Basic routing, DHCP, DNS, and ordinary firewall rules: a modern low-power x86 CPU is a sensible starting point.
- VPN, IDS/IPS, traffic analysis, or many connections: allow more CPU and memory headroom and validate throughput with the features enabled.
- 2.5GbE or 10GbE: verify both NIC driver support and performance for your actual workload; port speed alone does not determine firewall throughput.
Official OPNsense Minimum and Recommended Requirements
The official OPNsense Hardware Sizing & Setup documentation distinguishes minimum, reasonable, and recommended hardware for standard functionality.
| Configuration | CPU | RAM | Storage / Installation Target |
|---|---|---|---|
| Minimum | 1 GHz dual-core | 3 GB | 4 GB SD/CF with Nano image |
| Reasonable | 1 GHz dual-core | 4 GB | 40 GB SSD |
| Recommended | 1.5 GHz multi-core | 8 GB | 120 GB SSD |
Important distinction: the minimum tier excludes standard features requiring disk writes, such as certain caching and intrusion-detection logging functions. The recommended tier is a general starting point, not a benchmark for a specific internet speed.
How Much CPU Does OPNsense Need?
Basic Routing vs VPN and IDS/IPS
Routine routing, NAT, DHCP, DNS, VLANs, and basic firewall rules can be relatively modest CPU workloads. Encryption, packet inspection, logging, and large connection counts can demand substantially more resources. Two firewalls with the same WAN speed may need different hardware when only one is performing VPN encryption or deep packet inspection.
| OPNsense Workload | CPU Selection Direction | Example Platform |
|---|---|---|
| Basic home routing | Modern low-power x86 CPU | Intel N100-class platform |
| VLANs, multiple network segments | Low-power CPU; check interfaces and rule complexity | Intel N100 / N150 class |
| VPN-intensive deployments | Choose additional single-core and multi-core headroom according to protocol and encryption settings | Consider Intel Core i3-N305 or higher-performance options |
| IDS/IPS with substantial traffic | Prioritize verified inspection throughput, CPU headroom, and RAM | Evaluate stronger CPUs using tests with the intended ruleset |
| OPNsense running on Proxmox | Size for both the firewall VM and every other host workload | Evaluate host CPU capacity and resource contention |
These are selection directions, not measured performance tiers. Packet size, connection count, VPN implementation, ruleset, and enabled services all affect results.
Is Intel N100 Enough for OPNsense? N100 vs Core i3-N305
An Intel N100-based system can be a practical candidate for straightforward home routing and standard firewall functions. The Intel Core i3-N305 offers additional compute resources that may be useful for concurrent tasks or heavier services. Neither processor should be assigned a guaranteed VPN or IDS/IPS throughput figure without testing the specific hardware, OPNsense release, and configuration.
For processor generation and configuration differences, see our N100 vs N150 vs N305 vs N355 comparison.
How Much RAM and Storage Does OPNsense Need?
RAM: Start With the Workload, Not Just the Installer Minimum
OPNsense officially recommends 8 GB RAM for most standard use cases. Memory demand can rise with IDS/IPS, traffic analytics, large state tables, extensive logging, additional plugins, and virtualization.
For a new dedicated firewall, 8 GB is a sensible planning baseline. More RAM can be appropriate when the actual plugin set, traffic patterns, or workload requires it. If OPNsense is a VM, budget memory for the host and all other VMs or containers as well.
Storage: Why an SSD Is Usually the Practical Choice
The official reasonable tier lists a 40 GB SSD, while the recommended tier lists a 120 GB SSD. An SSD is generally preferable for installations that regularly write logs, updates, and other persistent data. The capacity needed depends on retention policies and installed services; a larger SSD does not automatically improve packet-processing performance.
Which Network Interfaces Work Best With OPNsense?
Intel NICs and FreeBSD Driver Compatibility
OPNsense is based on FreeBSD. Its official hardware guide notes the reliability and efficiency of Intel Ethernet NICs, but compatibility must still be checked for the exact controller revision and OPNsense/FreeBSD release.
Before buying or deploying a firewall appliance, verify the controller part number, port configuration, supported driver, and any release-specific issues. For example, an Intel i226-V-based system should be checked against the intended release instead of assuming that every OPNsense version behaves identically.
- Identify the installed NIC model and revision rather than relying on “Intel LAN” alone.
- Check the official OPNsense/FreeBSD hardware notes and relevant release information.
- Confirm that every interface appears, can negotiate the expected link speed, and passes a sustained traffic test.
- For SFP+ deployments, check module or DAC compatibility and switch configuration.
2.5GbE vs 10GbE: Port Speed Is Not Firewall Throughput
Multiple 2.5GbE ports offer flexible WAN/LAN separation and links to compatible switches or NAS hardware. 10GbE may be valuable for faster uplinks and networks that already use 10GbE equipment. However, a 10GbE NIC does not prove that the appliance can inspect, encrypt, or route traffic at 10 Gbps with every feature enabled.
Use a reproducible test with the actual enabled services to assess throughput, latency, CPU utilization, and thermal behavior before making a performance claim.
Hardware Requirements by OPNsense Workload
| Deployment | Practical Hardware Direction |
|---|---|
| Basic home firewall | Modern low-power x86 CPU; 8 GB RAM baseline; SSD; supported NICs |
| Home network with VLANs | Supported multi-port NICs, 8 GB RAM baseline, and CPU sized for routing/rules |
| VPN-heavy firewall | Choose CPU based on measured encryption throughput and concurrent tunnels |
| IDS/IPS and analytics | More CPU/RAM headroom; validate with the actual ruleset and logging settings |
| 10GbE network | 10GbE-compatible NIC, supported optics/cabling, and verified end-to-end throughput |
| OPNsense on Proxmox | Reserve CPU, RAM, storage, and network resources for the guest and the host |
Port count is also a design choice: you can separate WAN, LAN, guest, or lab networks with physical interfaces or use VLANs with suitable switching hardware. More physical ports do not automatically mean better firewall performance.
Bare Metal vs Virtualized OPNsense
A dedicated bare-metal firewall avoids sharing CPU and network resources with unrelated services. A virtualized firewall can be flexible for a home lab, but host maintenance, virtual switching, passthrough settings, and resource contention become part of network availability planning.
The official OPNsense virtualization guide states a minimum of 3 GB RAM and a minimum recommended virtual disk size of 8 GB for a VM. These are guest VM figures, not sizing guidance for a complete Proxmox host. The documentation also includes network offloading guidance for virtual installations.
For a production or always-on deployment, consider what happens to routing and internet access during host reboots and VM maintenance.
Frequently Asked Questions
What hardware do I need to run OPNsense?
OPNsense needs a supported 64-bit x86 system. Its official recommended baseline is a 1.5 GHz multi-core CPU, 8 GB RAM, and a 120 GB SSD. Select the NICs and CPU based on the intended firewall services and throughput.
Is 4 GB RAM enough for OPNsense?
Four gigabytes matches the official reasonable configuration. For a new deployment, the official recommended 8 GB provides more room for ordinary services. Heavy plugins and large connection counts can require additional memory.
Is Intel N100 enough for OPNsense?
It can be a suitable candidate for basic routing and standard home firewall use. VPN, IDS/IPS, and higher-speed workloads require validation on the actual device; CPU name alone cannot guarantee throughput.
How much RAM does OPNsense need for IDS/IPS?
There is no single universal requirement for every IDS/IPS ruleset. Start from OPNsense's recommended 8 GB baseline, then size and verify memory based on enabled inspection rules, concurrent connections, and logging requirements.
Does OPNsense support Intel i226-V network interfaces?
Support depends on the OPNsense release and its FreeBSD drivers. Check the specific release and controller revision, then verify interface detection, link negotiation, and stability on your hardware.
Can I run OPNsense on Proxmox?
Yes, OPNsense can run in a compatible virtualized environment. Allocate enough resources to the firewall VM and the Proxmox host, and check network configuration and maintenance implications before deployment.
Choose OPNsense Hardware Around the Workload
A practical selection sequence is required throughput → enabled firewall services → NIC/controller compatibility → physical port count → CPU headroom → RAM and storage. This keeps hardware decisions tied to an actual deployment rather than marketing specifications alone.
If you have already defined your workload and want to compare specific CWWK devices, see our CWWK firewall mini PC recommendations for OPNsense and pfSense.
To review current hardware options, explore the CWWK Firewall Mini PC collection. Confirm the configuration and compatibility of the individual model before purchase.
