SiFive HiFive Unmatched Hands-On, Initial RISC-V Performance Benchmarks
The microSD card included with the HiFive Unmatched was preloaded with the SiFive Freedom Unleashed SDK. This is SiFive's OpenEmbedded-based Linux distribution designed for developers to get going with the platform. When attaching a Radeon graphics card, 430 Watt ATX power supply, and all of the other connections, the HiFive Unmatched booted right on up to that Unleashed SDK.
The SiFive Freedom Unleashed SDK was working out fine and suitable for development purposes. Though there is also a growing number of Linux distributions supporting RISC-V, so I decided to spend most of my time experimenting with Ubuntu on the HiFive Unmatched given its expanded software selection, most users likely more comfortable on an Ubuntu-based platform than OpenEmbedded, and being more comparable to other platforms for the performance comparison testing.
There is this tutorial for Ubuntu on the HiFive Unmatched. It was surprisingly simple and easier than expected to get Ubuntu up and running on the HiFive Unmatched! Ubuntu 21.04 was running well on the HiFive Unmatched off the microSD storage.
It was also simple getting Ubuntu RISC-V running on the NVMe SSD, but an important item to note is that you still need to use the microSD storage with the installation there at least enough for having U-Boot running off of it. Booting directly to the NVMe solid-state drive doesn't appear possible without reprogramming the EEPROM but at least it's easy enough just leaving an install on the microSD card and from there modifying U-Boot to boot into the Ubuntu installation on the speedy NVMe solid-state drive.
Ubuntu's RISC-V build was working rather well and more software was available and working than I had anticipated. Even booting into the GNOME Shell desktop was possible with this Ubuntu RISC-V build. This was a rather pleasant experience and Ubuntu on the HiFive Unmatched working well enough that many could probably use it as a daily development system if so needed.