The Zotac wins the sustainability rating because it is the only test candidate that allows the replacement of RAM and SSD and consumes very little power (14 watts). The built-in power-saving processor does not need a fan, but is also a weakness of the Zotac: its power is enough for Offce and Internet - but not more.

The Zbox CI331 Nano is not a high-performance PC. You have to be aware of that. Moreover, it is not particularly frugal for a mini-PC when idle. The Celeron N5100 hardly blocks at all thanks to its four cores, but it feels a bit sluggish compared to modern Core i and Ryzen mobile processors...