Fujitsu S720 for a Home Assistant smart home setup – is it enough? I’m currently running my HA server in a Proxmox VM on this very machine. Here, you’ll learn exactly what my experience has been up to this point and whether I regret not opting for a higher model of this rather neat passively cooled thin client, such as the Fujitsu Futro S740 or S920.
My Experience With Home Assistant on the Fujitsu S720
The Fujitsu Futro S720 thin client was the heart of my smart home Home Assistant setup for well over 2 years now, and it still holds out really well. My HAOS instance is running virtualized on Proxmox with over 20 Zigbee smart devices in the network without any trouble, but that’s only half the story.
Here is everything you need to know if you plan to purchase a used Fujitsu Futro S720, or any Fujitsu thin client (or terminal as they sometimes call them) to host your Home Assistant OS instance.
Yes, almost all the remarks present in this little guide/review will be applicable to most of the other Fujitsu thin clients in from around this era as they are build in a very similar way, so if you’re thinking about going for an S720, S920 or any other Futro terminal, you can find still a fair amount of valuable info here!
While there are many other options seemingly similar to this one, including the Home Assistant Green box, different flavors of Raspberry Pi (pun intended) or a plethora of other thin clients or mini PCs, this one really offers a lot of features for a very low second-hand price.
Stable 15W power usage, a configurable “Power on AC” feature, passive cooling, silent operation, numerous I/O options, and the general ease of setup of this terminal are just a few reasons why I chose it over the other options I mentioned above, which I considered in the very beginning.
The fact that I found a used S720 for about $10 has also undoubtedly played a big part here. There are still quite a few deals like this available for instance here over on Ebay if you’d like to check out the current second-hand prices for this neat device.
If you want to know more about the S720 when it comes to its raw specs (besides the fact that it’s based on the 2-core AMD GX-217GA CPU), feel free to check its official specification table here, and its D3313 motherboard spec sheet available here, on the Fujitsu website.
How I Went About The Setup, Step-by-Step
There were only a few things that needed to be done before I could go through with installing Home Assistant OS. First of them was getting an mSATA drive for the main storage, as my used S720 came without one. I got a used 128GB one and promptly installed it. More on that in a short while.
Changing the thermal paste on the CPU is a matter of removing the screws to lift up the heatsink. It’s really simple, and you really should do it if you’re getting one of these used.
Other than that, the RAM didn’t really require an upgrade as the 4GB that were already installed were quite enough for running Home Assistant, and I didn’t need to install an additional wireless network card as I would be utilizing wired network connection anyway.
If you find that you need a Wi-Fi card on board, there is an additional mPCIe slot present on the motherboard for any compatible extension card.
After installing Proxmox with the aid of neat free software called Ventoy (which lets you create a bootable USB with many OS ISOs without reformatting the drive – very useful), I’ve put up a virtual machine on which I’ve installed the Home Assistant OS.
Upon getting the ZB-GW04 EFR32MG21 Zigbee Gateway dongle that you can see on the image above, connecting it to the S720, and passing its USB port through to the Home Assistant VM in Proxmox, I’ve set up the Zigbee2MQTT (you could also go with ZHA), and pretty much finished the initial setup.
After that, the only thing left to do was to turn on my smart devices (most of which were Zigbee devices at that time), and automatically pair them with the coordinator from within the Home Assistant user interface. And that was it for the setup.
If you’re not a tinkerer at heart, you could also very well install the Home Assistant OS directly on the S720, skipping the Proxmox/virtualization part entirely. I went with Proxmox mainly because I’m hosting a few different services on this client using both the Proxmox VMs and Linux Containers.
Want to know more about the Zigbee coordinator dongle I’m using here? Check out my full review and setup guide here: Cheap ZB-GW04 EFR32MG21 Zigbee Dongle – Review & Connection Guide
Now let’s quickly go through the other storage options you have on the S720.
The Storage Options
As already mentioned, the easiest storage solution for the Fujitsu Futro clients are the mSATA drives, like the small 128GB one you can see on the image above (which I also purchased second-hand).
The mSATA slot on the S720 is easily accessible, unlike the SATA slot which is hidden underneath the heat sink. To mount a mSATA drive in the Fujitsu Futro client you need only two M2 screws to fix it in place.
Connecting a SATA HDD or SSD drive is also an option here, although for that you would have to remove the CPU heatsink to access said single SATA port on the motherboard, use a SATA cable with a right-angle connector, and utilize the power connector next to the RAM sockets.
I’ve found a rather neat guide on how to connect an additional drive to the S720 and other Fujitsu thin clients here on YouTube, as well as a much more recent one, in written form (originally written in Polish). Check them out if you’re interested in that!
What I Really Like About It
So now, after all that time has passed, I can really get into all the things I really like about this little terminal, and at the very end its one obvious shortcoming.
First of all, something I’ve already mentioned in a few places: the I/O including 2x USB 3.1 ports and 5x USB 2.0 ports, as well as and a DisplayPort output is really nice to see. It also features two separate sets of audio ports, in front and in the back of the device.
The fact that it has legacy DVI-I, VGA and PS/2 outputs on board is pretty welcome too. Oh, and a Kensington Lock is present here too.
When it comes to power usage, the S720 draws stable 15W of power both when idle and when handling most Home Assistant related tasks like device management and setup. In comparison, a Raspberry Pi 4 uses 3-7W on average depending on the load. Both devices are passively cooled and feature no fans.
As you’ve already learned it can run Proxmox with a few lightweight containers without trouble, it’s relatively small and compact at the same time having quite a bit of free space inside the case, after changing one setting in BIOS it can be configured to automatically boot on AC power (extremely useful for automatic reboots after power outages) and it’s dead silent not featuring any mechanical elements, provided you use a HDD instead of an SSD (as you should), and you’ve unplugged the mainboard speaker.
This, paired with the extremely low prices of the used S720s makes them one of the better choices for a Home Assistant server machine if you don’t need much power for handling more demanding tasks like hosting game servers or handling large media files.
What Still Bugs Me (Just a Little Bit)
First, and the most important thing is that this thing doesn’t really have any significant horsepower to it, especially if you compare it to anything like an average low-end modern Mini PC.
This simply means that you most probably won’t be able to run any CPU-intensive software on this one, and this includes media servers with live encoding, more complex voice recognition pipelines, or, obviously any local LLM programs which nowadays are more and more present in experimental Home Assistant setups.
The 2-core 2-thread AMD GX-217GA CPU on the S720 is very power efficient and it handles Home Assistant alongside with a few other simple services without any trouble, but it’s by no means a speed demon. For multi-threading tasks, even a device like the way smaller Raspberry Pi 4 can potentially do much better.
Still, I do think that in a sense, a thin client like this has quite a few advantages over a RPI setup, mainly in the field of easily accessible and plentiful I/O options, and general expandability (RAM and storage upgrades, free mPCIe slot, and so on).
Would I Get It Again? – Is It Still Worth Getting?
My answer to that is yes. It’s sleek, it’s powerful enough to handle Home Assistant running on Proxmox, and lightweight services such as Pi-Hole. It’s also extremely cheap and can be purchased for much less than a new Raspberry Pi 4/5, which albeit more powerful, are also increasingly hard to get.
Although someday I think I might upgrade to a larger and more beefy unit for my NAS and media server (or purchase a completely separate machine for that matter and get into Proxmox clusters), for now it’s more than enough for what I’m doing. If you can find one for a good price, I wouldn’t think twice. Hope I was able to help!