Hands-on CachyOS is a performance-optimized rebuild of Arch Linux, with a simpler installer and dozens of desktops and options to tweak. Stable reliability, not so much.

CachyOS is an Arch-based Linux distro which brings easier installation plus an almost bewildering array of performance optimizations. Like Arch in general, it's aimed at moderately experienced Linux users who want to try out the latest file systems and kernel options such as alternative schedulers. At risk of stereotyping, we feel it might suit the sort of tech enthusiasts who have heatsinks on their RAM, overclock their CPU, and change graphics cards several times a year.

Like Arch itself, CachyOS is a rolling-release distro, but the project publishes fresh installer ISO images about once a month. The 2407 release came out just a few days ago, and is the first distro The Reg FOSS desk has seen with the newly released kernel 6.10. We've been meaning to try CachyOS since the May release, which was the first distro we heard about to offer the option to install the OS onto the new bcachefs file system, which debuted with kernel 6.7 at the start of this year.

Arch itself has been around for a couple of decades now, and remains a do-it-yourself sort of distribution. This has encouraged multiple meta-distributions based on Arch, each with their own value propositions. Manjaro Linux, which we last looked at in May, does more testing and integration on Arch's continuous flow of new packages, aiming to deliver a smoother experience for those wanting comfort more than speed. EndeavourOS, which we reviewed in 2022, sticks directly to upstream packages, but wraps them in a simpler installer, with a choice of editions with different desktops. Garuda OS, which we also tried in 2022, has lots of tools for tweaking settings, a bold and colorful look and feel, but most importantly adds openSUSE-style snapshot support and rollback, which are valuable things to have with a rolling-release distro.

Although it uses the easy Calamares cross-distro installation program, we had serious difficulties getting CachyOS running, both in two different hypervisors and on the bare metal of our trusty testbed quad-core ThinkPad W520. Installation is consistently very slow. Despite downloading a just over 2.5 GB installation image, the installer won't start until you make an internet connection because it always installs packages from the online repositories. For anyone on a metered internet connection, this is a very bad option. We feel the installer should offer you a choice, but it doesn't.

The installer offers every conceivable option of disk format - including bcachefs - but it defaults to Btrfs. On UEFI machines, it also offers a choice of bootloaders. However, we had repeated problems with installation failing to complete: Several times, but not only, at the final stage of installing the bootloader.

In theory, this isn't a deal-breaker on a multi-boot machine like our testbed ThinkPad. We had to mount the CachyOS root partition for the Ubuntu version of GRUB's os-prober to find it, but it wouldn't boot, giving an error:

error: file '/boot/vmlinuz-linux-cachyos' not found.
error: you need to load the kernel first.
Press any key to continue...

When bootloader installation fails, there's no option to retry or continue. You must restart the whole installation. The installation media is slow to boot because it copies the live system into RAM, but even with 24 GB of memory, it doesn't cache the package files. So when you have to retry the installation, it re-downloads all the packages again. The installer was also unable to pick up an existing swap partition, even when pointed at it, and installed the ZRAM in-memory swap daemon instead.

Although the live medium boots up with KDE Plasma 6, the installer offers an unusually wide choice of desktops and window managers, including less commonly seen choices such as Cutefish and UKUI, the Chinese desktop from Ubuntu Kylin and OpenKylin. We tried both of these, as well as Budgie and MATE, the latter being the latest version 1.28. Both UKUI and Cutefish consistently failed, with the window manager not starting. This left us with part of a desktop, but one where you can't move, resize, or switch between windows. We had this problem in VirtualBox, in UTM, and on bare metal, so it wasn't driver or hardware related. Offering so many choices is good, but not at the price of inadequate testing and integration. Budgie and MATE both worked very smoothly, though.

Both the live medium and the installed system have a friendly welcome screen dubbed "Hello". As well as handy but not unique options such as a software installer (which reminded us of the one in MX Linux), an updater, and links to forums, documentation and so on, there are some less common options. A "tweaks" screen has options to adjust settings, enable aggressive memory-usage and processor-hogging management tools, and other global adjustments. There's also a button to launch the CachyOS Kernel Manager, which lets you choose between 23 different kernel versions, including LTS releases, hardened builds, real-time builds, different process schedulers, and more. There are also repositories compiled for different revisions of the x86-64 instruction set, as well as for the latest AMD CPUs - none of which helped at all on our vintage 2011 Thinkpad, whose onboard NVIDIA Quadro 1000 GPU isn't supported by any of the kernels or drivers on offer. This is definitely not a distro for lovers of classic hardware.

Aside from these tools, the bundled options are relatively sparse. There are some extra monitoring tools, such as the text-mode btop tool, two terminal emulators - your desktop's one plus Alacritty - and a custom build of Firefox called Cachy-Browser, which resembles LibreWolf and comes with uBlock Origin preloaded. We were surprised to find the GNOME Meld visual file-comparison tool, which seems like an odd inclusion.

On our well-specified yet aging hardware, we're sorry to say this distribution did not live up to its boot screen logo: CachyOS! Blazingly Fast. Arch isn't an especially lightweight distribution; if you install it yourself in the traditional way, you can omit significant chunks of the OS if you don't need them, such as printing support - but that's not an option for downstream meta-distros that wrap Arch in an easy installer like this. With MATE, it idled at about 850 MB of RAM, and about 950 MB in Budgie, and a clean install took over 6 GB of disk space.

If you build your own high-spec, frequently upgraded computers, want high performance for media or development or gaming, and know enough Linux to want to start tweaking and experimenting without building your own system from scratch, this is an option. Saying that, though, if you want to wring out every scrap of performance, you might be better off learning raw Arch, then moving on to, say, Gentoo - which goes much further in letting you really customize your OS to precisely match your custom PC.

We were disappointed to hit so many bumps and errors in a modern distro. It was a like a flashback to the bad old days around the turn of the century. With well over a dozen desktops to choose from, it felt to us like they were spreading themselves too thin, especially given the problems we had with the two least-common ones. Choice is good, but there's such a thing as an embarrassment of riches, especially when some options are flaky. ®

https://www.theregister.com//2024/07/23/cachyos_arch_linux/