Asus may not be your first thought when you start looking for a mini-PC, but the company has a fair few on offer. Its most recent releases, the PN40 and PB40, are fanless designs that differ only in size and external connectivity. Let's check 'em out.
Asus PN40 mini-PC
The PN40 is a general-use device aimed at home users, while the PB40 is aimed at businesses and offices looking for quiet-and-compact workstations. Both machines have a square footprint: 4.5" (11.5 cm) on a side for the PN40, and 6.8" (17.5 cm) on a side for the PB40. They differ slightly in thickness too. The smaller PN40 is slightly boxy at just under 2" thick (4.9 cm), while the PB40 is slimmer at 1.3" (3.4 cm).
Asus PB40 mini-PC
The hardware inside either model is the same. You get the option of Gemini Lake Celeron N4000 or Celeron J4005 SoCs. Both chips have two CPU cores and 12 GPU EUs, but the 10-W J4005 starts at 2 GHz while the 4.8-W N4000 runs at 1.1 GHz by default. Either CPU will burst to over 2.5 GHz for short intervals. The Asus mini-PCs come with two SO-DIMM slots that support DDR4 memory at up to 2400 MT/s, and room for both 2.5" and M.2 storage. They also can be purchased with up to 64 GB of eMMC flash.
Asus PN40 external ports diagram
The other big difference between the PN40 and PB40 is in their external connectivity. As befits its consumer-oriented design, the PN40 has an HDMI port along with Mini-DisplayPort and VGA connections. The machine gets a single USB 2.0 port, four USB 3.0 ports (one in Type-C flavor), a combo audio jack, and a Gigabit Ethernet connection. For those looking to use the machine in embedded environments, the VGA connection can be replaced with a legacy serial port, though it's not entirely clear if this is an option or something the user can do himself.
Asus PB40 external ports diagram
Meanwhile, the PB40 has a few more options. The HDMI port makes way for a full-sized DisplayPort. There are six USB 3.0 ports (one of them Type-C) as well as the one USB 2.0 port. This model has a dedicated mic-in jack besides the audio output combo port, and it comes with a legacy serial port as standard. Interestingly, the PB40's VGA jack can apparently be switched out for another serial port or DisplayPort connection, though once again it's unclear if this something done at the factory. There's also an RP-SMA connector for an external Wi-Fi antenna.
Asus hasn't announced pricing for the mini-PCs yet, but they'll apparently come in a plethora of varieties given all the options on offer. There will also be barebones versions for folks who'd rather do it themselves. These machines should be available any day now, so if you're keen to try out Gemini Lake, keep an eye out. Thanks to TR tipster SH SOTN for the heads-up.