Unraid is a closed-sourced Linux based home server / NAS operating system. It offers a WebGUI and supports virtualization with Docker and Virtual Machines. The intended use is really versatile.
But what hardware requirements does Unraid need?

Unraid itself is very frugal and runs on any 64bit processor with 1Ghz+ and 2GB+ RAM. In addition, a USB stick with at least 1GB of memory is required.

Unraid Hardware Requirements

The hardware requirements for Unraid are given for three different categories. Once for a pure storage server, for an application server and for a VM host server.

Data Storage and Protection

The minimum hardware requirements to install Unraid OS 6 for data storage usage are:

1. A 64-bit capable processor, 1.0 GHz or better
2. At least 2GB of RAM
3. Linux hardware driver support for storage, Ethernet, and USB controllers
4. Two hard disk drives to ensure data protection with a parity disk

Additional requirements apply when adding applications or virtual machines.

Application Server

To run a wide gamut of applications your system should consist of at least a quad-core CPU (2.4 GHz or faster) and 4-8GB of RAM. As you load more applications you load, you’ll need to add additional resources.

Creating Virtual Machines

To run VMs, you must have hardware-assisted virtualization (HVM) support on your processor/motherboard (Intel VT-x / AMD-V). To assign host-based PCI devices, like graphics and sound, to your VMs, your CPU and motherboard must also support IOMMU (Intel VT-d / AMD-Vi).

Each of the three types of VMs you can create using Unraid OS 6, have slightly different requirements for virtualization support.

What hardware requirements do I need for my Unraid server?

Of course, it depends on what you want to do with the Unraid server. Nevertheless, I list some examples.

If you use the Unraid server at most for file storage and maybe one or two Dockers like Nextcloud, a 2 core CPU with 8GB RAM can be sufficient. But I would generally recommend at least 4 cores and 16GB.