What is Mini-STX? You’re certainly forgiven if you ask. A compact kind of mini desktop that has seen only limited adoption, Mini-STX saw an initial flurry of activity a couple of years ago, then fell mostly dormant. Although compact computer parts adhering to the Mini-STX spec have the potential to challenge the MicroATX and Mini-ITX form factors, so far most folks, even dedicated DIY types, don’t even know they exist. Asrock, one of the pioneers, isn’t giving up on it, and the company now aims to bring easy-to-build little PCs based on the spec to the masses with the bare-bones DeskMini 310 ($164.99). It’s a powerful design for anyone willing to assemble a small desktop by applying some judicious component-choosing and finger dexterity. The fact that it hosts up to three drives and takes socketed Intel desktop CPUs adds to the flex appeal and power potential. It’s a worthy choice to Intel’s NUCs, many of which rely on mobile-grade chips.
An STX Lookaround
In short, Mini-STX computers are among the most compact CPU-customizable PCs available today. The design is based around a square 5×5-inch motherboard. Mini-STX PC cases are typically just slightly larger than this and stand just a few inches tall. The finished product is roughly the size of a traditional desktop-PC power supply.
As you’d guess, real estate on Mini-STX motherboards is at a premium. To help save space, they require the use of SO-DIMM memory, the kind used on many laptops. These computers also typically lack PCI Express ports, which means you’re reliant on your specific CPU’s on-chip graphics. (A more obscure variant, Micro-STX, factors in dedicated graphics modules.)
Before I crack open this particular egg and see what’s inside (hopefully not yolk), let’s have a look at the DeskMini 310’s exterior. The case measures 6.2 inches square (just a smidge bigger than the motherboard) and 3.2 inches thick. If you look at the image posted above, you will see two DeskMini PCs sitting side-by-side, but they are in fact not the same system. One is the newer DeskMini 310; the other is an older DeskMini 110 model. From the outside, they look the same. The changes Asrock made are all inside.
In general, the DeskMini 310’s looks are unremarkable, with an aesthetic best described as “black cube minimalism.” As the main point is creating a compact, unobtrusive system for productivity work (in an office, at a point of sale, or tucked in a desk niche), this lack of flair is fine.
Asrock currently sells three versions of the DeskMini 310. The base-model DeskMini 310, as well as the DeskMini 310W, are built around Asrock’s H310M-STX motherboard, whereas the DeskMini 310 I have on hand for this review, the DeskMini310/COM, uses a slight variant board, the H310M-STX/COM. The only difference between these two boards is the existence of a COM header on the latter. Otherwise, their specs are the same, and they look almost identical. They look quite close to the motherboard used on the older DeskMini 110, too.
The key change on the new H310M-STX motherboards is the use of the H310 chipset, which brings with it a host of feature enhancements over the H110M-STX board (and H110 chipset) used in the older DeskMini 110. Most notable is the support for Intel’s 8th and 9th Generation processors on the LGA1151 socket.
That compatibility is a big deal. It offers the potential for significantly more performance, thanks to the ability (depending on the chip) to get an increased core count versus the older 6th and 7th Generation chips supported by the DeskMini 110. Any 8th or 9th Generation Intel processor with a TDP of 65 watts or less will work on this board.
For this build, I used a budget-minded Celeron G4920. In theory, though, you could put a chip as robust as the six-core/12-thread Core i7-8700 (not the “K” one, mind you) in here. But this PC is likely more aligned with the Core i3s, Celerons, and Pentiums of the world, given the budget bent.
Otherwise, little else changes on the motherboard from one generation to the next. The audio chipset was changed to a Realtek ALC233 on the H310M-STX (versus the Realtek ALC283), and both boards use the same Intel Gigabit Ethernet controller. The new board also comes in a slimming black color with black heatsinks over the VRMs instead of silver ones, but that’s only academic; the case doesn’t have much visibility inside apart from perforations on the cover.
To save space, as mentioned, this motherboard uses SO-DIMM DDR4 memory modules. This type of memory is typically reserved for notebooks, but its small physical footprint is essential to making everything fit on Mini-STX motherboards. This board supports memory at clock speeds up to 2,666MHz, which should help to boost performance somewhat, compared to the last-generation H110M-STX board, which was capped at 2,133MHz.
If you plan to buy one of these systems, I should reiterate: Don’t ignore that 65-watt TDP limit I mentioned on any processor you drop into this motherboard. Though a power-hungrier chip would fit in the socket, it would be unwise to try to push this limit, as the board has just a handful of voltage regulation modules (VRMs) available to step down power to the processor. The power supplied to the PC is also a limiting factor, as the power supply included with the DeskMini 310 can put out a maximum of just 120 watts. (For more on VRMs and other motherboard lingo, see our guide to motherboard terms you need to know.)
For keeping the processor and the system as a whole cool, your options are limited. Intel’s stock LGA115X cooler is a viable solution, but just a few aftermarket coolers are compact enough to fit inside the case. You get just a few millimeters of space between the top of the case and the top of Intel’s stock cooler, but this gives us a fairly good guide to go by when searching for other thermal solutions. The stock cooler measures 95mm square and 60mm high, and any potential aftermarket coolers will need to fall within these dimensions to work inside the DeskMini 310. I’d suggest sticking with stock to be safe.
Mounting Storage, and Some Mobo Notes
You get three drive mounts: one on the motherboard (M.2), and two in the chassis.
The chassis gives you room to mount two 2.5-inch storage devices, both of which reside below the motherboard. One of these mounting locations is easier to use than the other, as it has a semi-toolless mounting system. One side of the drive slides into place and is held by metal notches on the side of the mounting tray. You still need to use two screws to secure the drive in place.
If you want to use the other 2.5-inch drive mount, you will need to remove the motherboard to attach the drive securely to the mounting tray. You don’t get any easy mounting hardware to help you here. This is one spot I feel that Asrock could improve; I can’t see a clear reason why this drive position couldn’t use an identical mounting system as the other. The exterior of the case does block you from adding screws to the case’s side, but a snap-in solution seems like it should have been viable.
After fastening the drives to the case, you use one cable to connect the drives to the motherboard. This cable supplies both data and power, and it connects to the underside of the motherboard. It’s a custom connection, like so…
As for the M.2 Key-M mounting spot on the motherboard, there isn’t anything remarkable about it, apart from the fact that it exists at all on a board this small. (It supports both PCI Express/NVMe x4 and SATA drives, up to 80mm long.) The fact that the DeskMini 310 can host up to three drives in such a small chassis is a big plus. Think about it: A couple of 2TB 2.5-inch hard drives and a 1TB M.2 SSD could net you 5TB of local storage in this little box, and that for conceivably less than $300 for all three drives.
Something to consider, though, about the storage scheme for longer-term viability: If you are considering switching the motherboard out for a different one, you will want to watch carefully how storage devices connect to the new motherboard to see if a new board will work inside of the DeskMini 310 enclosure. Asrock didn’t leave space for any cables to pass from the hard drive bay through to the top side of the motherboard. This means that unless you purchase a motherboard that has storage connections in the same place on the bottom of the board, you will not be able to connect storage devices to a third-party motherboard inside this case.
It is possible to change the motherboard, though, and this also won’t affect the front panel. The Mini-STX form factor dictates that all Mini-STX motherboards have a 3.5mm headphone jack, a USB 3.0 Type-A port, a USB 3.1 Type-C port, and a mic-in jack on the front edge in the exact same order and spacing. In a nutshell, if you don’t regard 2.5-inch drives, any Mini-STX motherboard should work in this case.
There’s also a spot to add a Wi-Fi module (a 30mm M.2 one) on the motherboard. This slot sits directly below the M.2 Key-M slot, which means you will want to add any Wi-Fi module first, before any M.2 storage devices, as the Wi-Fi mounting position will be covered up by anything in the M.2 slot. If you do install M.2 Wi-Fi, notches in the rear of the case can snap out and let you add up to three Wi-Fi antennas.
Asrock includes an Intel AC-3168 Wi-Fi module in the DeskMini 310W barebones kit, along with two antennas. This Wi-Fi module supports 802.11ac and Bluetooth 4.2. The base-model DeskMini 310 and the DeskMini 310/COM do not include this module, however.
The Wi-Fi module and antennas appeared to work quite well in my brief performance tests. Making use of Speedtest.net’s online utility, the DeskMini 310 was able to achieve a download speed of 111.8Mbps and an upload speed of 10.7Mbps, which is the max speed I get from my ISP on my current Internet package. (Disclosure: Speedtest.net is run by Ookla, which is owned by PCMag’s parent company, Ziff Davis.)
Mounting Optional Case Features
You’ll note two locations where you can add optional extra ports to the DeskMini 310’s case exterior. On the rear I/O is a spot that can fit a legacy serial port. This is likely not something that most people will use, but it’s important to keep in mind that this system, in its different guises, targets consumers and businesses, and plenty of businesses still use legacy hardware that connects via a nine-pin serial port: point-of-sale scanners, factory equipment, and the like. This port can only be used if you purchase the DeskMini 310/COM, though.
What will undoubtedly be more useful to everyone is the pair of optional USB 2.0 ports you can install on the top of the case. These can be a little tricky to mount, as you need to hold the ports in place and screw them on from the outside. I have somewhat small hands and found it a tight fit to get my mitts in the case during this process, so I’d hate to think about how difficult this process would be for someone with bear paws.
I can’t see why Asrock doesn’t just sell the DeskMini 310 with these ports pre-attached, apart from possible cost reductions. There’s no such thing as too many USB ports in today’s world, and the ports don’t impede any other part of the build process.
The DeskMini 310 also supports 75mm-by-75mm and 100mm-by-100mm VESA mounts, sold separately. (I saw them on Amazon for about $15 at this writing.) The VESA mount is easy to install and doesn’t require you to open the system. Just fasten four screws on the bottom of the case, and screw the other half of the VESA mount onto the mounting rack. From there, you just push the two halves of the mount together and give the mount a slight turn, and it locks in place on the DeskMini chassis.
Closing the DeskMini 310 can be a bit challenging, especially if you are using some of the extra case accessories. There isn’t much room for cables inside of this case, and when you close it, all of the cables tend to move into problematic locations, such as into the path of the fan blades on the CPU cooler. If any of the cables are situated too low in the case, they may also block the case from closing fully.
Working around this requires some dexterity. At first, I tried using twist ties to bind the cables to the top of the case so that I could get the unit closed. This didn’t keep the cables out of the fan, but by removing the twist tie and freeing the cables afterward, I was able to use a paperclip to push the cables safely out of the way. If you run into this problem with your own DeskMini, this is the best method I could think of to get the case to close properly.
A Quick BIOS Tour
Asrock doesn’t recommend upgrading the BIOS on the H310M-STX or the H310M-STX/COM beyond BIOS version 3.4 unless you are encountering system stability problems. You will not be able to downgrade the BIOS after upgrading. (Asrock has copious warnings on its support page.) Still, I wouldn’t be doing my job if I didn’t try this myself, but in my case the upgrade went smoothly. It just took about a minute to complete.
I should note that I wasn’t able to upgrade the BIOS from inside of the UEFI. I had to use the Windows-based BIOS upgrade utility, but I encountered no problems with the process or with the upgraded BIOS.
The BIOS is ordinary by today’s standards. It features a click-friendly interface and provides basic information about the system’s hardware and specs. The EZ Mode menu gives you access to the boot order and XMP memory profiles, and it also has tools to upgrade the BIOS and adjust the CPU fan speed.
The Advanced BIOS menu has more to offer, including an OC Tweaker feature. Don’t get too excited, though; you can’t really do any overclocking here. Despite having some OC-friendly features, this is an H310 chipset, and you can’t mess with the CPU multiplier. You also don’t get access to the BCLK, which is unfortunate, though not from an overclocking standpoint; if you desire higher efficiency, you can’t work with the system voltage and undervolt the CPU. Really, there’s not enough room for a proper thermal solution in the case to bemoan any lack of overclocking features.
The RAM-overclocking options on this board are rather limited. Officially, the board supports DDR4 at speeds up to 2,666MHz, and the 16GB DDR4 memory kit I used for this review (which comprises dual 8GB SO-DIMMs) clocks in at 2,166MHz with timings of 13-13-13-35. I was able to overclock this kit to 2,400MHz in a few seconds, but there wasn’t any option to push the RAM to the board’s maximum rating of 2,666MHz. This holds true for both BIOS versions I tested. Possibly, an SO-DIMM DDR4 memory kit that has XMP support for 2,666MHz might be able to go higher.
Get Socketed and Small, the STX Way
On the whole, the DeskMini 310 is a well-done iteration of the DeskMini 110 that helped Mini-STX get a bit of momentum going a few years ago. Upgrading the system with a modern motherboard that supports Intel’s 8th and 9th Generation CPUs gives it a notable bump in potential performance, courtesy of the higher core count in those processors, and the improved RAM speed will also help performance in some situations, especially those that lean heavily on the CPU’s integrated graphics.
We do wish that Asrock had made more of an effort to improve the building and cable-routing experience of the DeskMini 310 in this new generation. It just takes patience, however, like any other supercompact PC, and is a minor point. We’d also like to see the extra USB ports included as an accessory in the box.
But on the whole, if you’re looking to build out a compact dynamo to your specifications, the Mini-STX-based DeskMini 310 makes for a nice alternative to an Intel NUC, thanks to its greater motherboard surface and support for socketed desktop CPUs, rather than the mobile chips that most NUCs rely on. If leveraging cores and threads in a little PC is what you’re after, it’s a worthy DIY project, and businesses can also use the COM variant to build simple systems that leverage legacy hardware with little trouble.