Arm64 on the desktop? It’s spendy and it’s sluggish

A Red Hat build engineer has ended his second experimental effort at using a high-end Arm64 desktop computer as his daily driver. His conclusions are instructive. Marcin Juszkiewicz's series of posts on his tech blog about running a Fedora-powered beast of an Arm desktop computer has been interesting reading for about a year now. Almost exactly a year ago, he built a beast of an Arm workstation. He spent some 1,800 building a machine around an Ampere Altra, which as The Register described in 2020 is a serious bit of kit. And even at 1,800 (1550, or $2000) quite a bit of it was second-hand, including the CPU and RAM. He described the machine's capabilities in Arm desktop: 2025 attempt, part one. We were considering a story about the sheer cost of the kit, but his latest update describes The end of the AArch64 desktop experiment. That means it's now more of a post mortem. To cut to the chase, he has switched back to using his AMD Ryzen 5 3600 system: the six cores of a $199 chip from 2019 outperforms an 80-core Arm64 powerhouse. Juszkiewicz, who also goes by the rather easier to spell hrw, knows his stuff, and he is a man of strong opinions. Indeed, his Mastodon profile gives a clue: Tired of Seriously Bad Computers (SBC) so moved to Arm servers and virtualization." SBC, of course, more normally stands for Single Board Computers" in this industry, and by far the best-selling Arm SBC is the Raspberry Pi. As it happens, we've met him: the Reg FOSS desk attended a talk by Mr Juszkiewicz at the 2016 Flock to Fedora conference. We already knew that he wasn't a fan of the Raspberry Pi devices. Also, for any doubters out there, this Altra box was not his first attempt to build an Arm64 daily-driver machine. That was back in 2015, as he described over three posts. AArch64 desktop: day one talked about the spec, involving a Mustang motherboard - which means an Applied Micro X-Gene X-C1. By day two, he started to cover issues with his distro: "I use Fedora on my machines. And as lot of people know this distribution has strange rules when it comes to multimedia support. Forget about MP3, H264 and few other things." The post talks about needing to build his own codecs and media player applets, the lack of Macromedia Flash support, and more. We note this just in case anyone is tempted to jump to the conclusion that his more recent Arm experiment failed due to a lack of knowledge or skills - he definitely has both in large amounts. After just four days, he wrote AArch64 desktop: last day, discussing the performance issues of an eight-core, circa 2.4 GHz ArmV8 computer: "OK, I can be spoiled by speed of my i7-2600k desktop but situation when Firefox with less than 20 tabs open is unable to display characters I type into textarea fast enough shows that something is wrong (16GB ram machine). And tell me that this is not typical desktop use of web browser..." He spares judging the machine too harshly: "I think that results may be affected by a fact that all I have here is Applied Micro Mustang based on X-Gene 1 cpu. It is one of first ARMv8 processors in Linux world and it is optimized for server use rather than desktop." Well, fast forward to 2025, and he still has no choice but to use a manycore Arm64 chip aimed at servers, rather than the desktop. As The Reg reported earlier this month, they are now a serious force in the server and datacentre market... but aside from Apple Silicon, not on the desktop or in laptops. This time around, in Arm desktop: 2025 attempt, part one, he starts by setting the context: "Almost ten years ago, I tried to use an Applied Micro Mustang as a desktop. And it was painful. " He also starts out with some of the problems. Even a decade on, he still has problems with missing codecs and client apps. The steps needed to work around them have changed, but the situation is not massively better. Last time, for instance, it was a problem that there was no Flash player; now, there's no Arm Spotify client. In the second installment, Arm desktop: emulation he looks at the problems of using the latest x86-on-Arm emulation tools in trying to run x86 games on even a high-end Arm chip: "Test results were awful: Single core: 459 Multi core: 4110 That's the level of an Intel Atom CPU from 2021." He concludes: Let me be honest: without tweaking FEX-Emu config it was unplayable." The third installment moves on to the issues of this server part: Arm desktop: so many cores, not enough speed. "Having 80 cores sounds nice, doesn't it? But not so much during actual use... You see, building Fedora packages was flying by. With all cores in use, ccache buffers filling up (in case of rebuilds), and 128 GB of RAM in constant use, etc. "But at the same time, 100 percent load on all cores means you cannot listen to music on Spotify or watch online videos, etc. All that because the CPU cores are occupied by the build processes." His summary is short but not very sweet. The main issue: The lack of single-thread speed." And the bottom line: To use a desktop system you do not need many cores. As long as they are fast." In the final instalment, The end of the AArch64 desktop experiment, he looks at some of the issues in depth. He built his own custom specially patched kernels; he tried two different GPUs - both an AMD Radeon RX6700XT, a high-end card that was $479 when new in 2021, and then an Nvidia RTX 2060, a card that was $349 in 2019. With both cards, some apps wouldn't run, due to missing OpenGL libraries, or they ran very badly: Watching YouTube videos became impossible due to 720 out of 750 frames being dropped, etc." He hasn't pensioned off the machine: "The 'wooster' system stays powered on, churning through RISC-V package builds. It may be weak in single-thread, but it flies when it comes to multi-core load. " But this is the end for now: "As for the Ampere Altra, I am not planning to repeat this experiment. Another AArch64 desktop attempt would require a completely new hardware platform. And I have no plans to spend over twenty thousand PLN to buy an Nvidia DGX Spark system." (Twenty thousand Polish zoty was around $5,305, 4,020, or 4,660 at current exchange rates at the time of publication.) Our original plan when hrw" started this series was to look into the lack of commodity-priced Arm64 hardware. At last year's Ubuntu Summit, System76 presented its nearly ready COSMIC desktop, but it also demonstrated its 128-core Altra workstation, the formidable Thelio Astra. With half a terabyte of RAM and 40 TB of storage, it's a snip at just over $6,000 (4,600). We have to admit, after reading Hrw's in-depth stories of what went wrong, we no longer covet one. Perhaps paying 168 for an 8 GB Pi 5 isn't so bad after all. (R)