A Closer Look

Much like the 4X4 BOX-7735U/D5 we reviewed previously, ASRock maintains a similar design with the 4X4 BOX-7840U. The top section of the unit remains functionally identical to previously reviewed units, with the plastic housing featuring subtle indents that provide a touch of visual appeal to an otherwise unadorned exterior. In the bottom left corner, you'll locate the power button. When you flip the system over, you'll observe four screws securing the chassis, with two mounting holes designed for the VESA bracket placed in the center. It's worth mentioning that the glossy plastic exterior tends to attract fingerprints, but since the unit is primarily optimized for use in digital signage systems, office work, kiosks, and home media centers it likely won't be a huge deal.


The Front I/O consists of a USB 3.2 Gen 2 Type-A port and 2 USB4 ports that also support DisplayPort 1.4a. More importantly, the unit does offer eGPU support which I can 100% confirm with my Akito Node Titan unit equipped with a pedestrian GeForce GTX 1650. This opens up the system to many new usage scenarios and even as a full-on gaming PC, as you could utilize an eGPU for both a laptop and this system for gaming purposes. Beyond the two USB4 ports, ASRock has opted to include a 3.5 mm Microphone / Headphone combo jack on the front as well. Meanwhile, the right side has a vented opening for cooling, although it is somewhat restricted, which may come into play later on.


Examining the back I/O, you'll discover a set of 2 USB 2 Type-A ports, 2x HDMI 1.4b ports which are sadly limited to 4K 30 Hz, a 2.5 GbE LAN port, a 1 GbE LAN port with DASH support, a power plug, and a Kensington lock. While the system's I/O array offers excellent functionality, it does come with some limitations, as additional USB ports would require the use of a Type-C to Type-A hub or adapter. This means it falls short when compared to a full-fledged desktop, yet proves well-equipped when considering its compact size or in comparison to most slim and lightweight laptops. Notably, the 4X4 BOX-7840U can handle up to four displays simultaneously and is equipped with Wi-Fi 6E and Bluetooth 5.2, courtesy of the RZ616 WiFi module. Overall its well balanced for a Small Form Factor (SFF) system or Mini-PC. Oh and before moving on, the right side has a vented opening to enhance airflow.


To power the system, ASRock opted for an AcBel 120-watt power brick.


Finally, to get the system operational I opted to use a Western Digital SN770 1 TB NVMe SSD and a 32 GB dual channel SO-DIMM kit of Kingston Fury Impact DDR5 5600 MHz (2x 16 GB). For the OS I opted for Windows 11 Pro.