ASRock Industrial 4X4 BOX-7735U UCFF PC Review: Zen 3+, RDNA2, and USB4 in a Potent Platform

ASRock Industrial is one of the few vendors with a lineup of ultra-compact form-factor (UCFF) computing systems based on the latest Intel and AMD platforms. Their lineup of NUC clones - the NUC BOX series with Intel, and the 4X4 BOX series with AMD - has enjoyed significant market success, mainly due to their commitment to leading edge processors. The company introduced the 4X4 BOX-7000 series UCFF PCs based on AMD's Rembrandt-R SoCs in early February, and sent across their flagship SKU - the 4X4 BOX-7735U/D5 - to be put through our rigorous evaluation routine.

The 4X4 BOX-7735U/D5 is one of the first UCFF mini-PCs to rely on DDR5 SODIMMs, and it is the first AMD-based mini-PC in our labs to include USB4 functionality with PCIe tunneling. The process improvements in moving to Zen 3+ and a re-architected integrated GPU (RDNA2) should theoretically deliver significantly better performance and power efficiency for a range of workloads over the company's Cezanne-based flagship (4X4 BOX-5800U) from last year.

The Ryzen 7 7735U, despite being a Zen 3+ part, was actually introduced only in January 2023. With a TDP of 28W, this U series SKU is meant primarily for notebook platforms. However, its deployment in an actively cooled UCFF chassis has allowed ASRock Industrial to provide the end user with a bit of flexibility in terms of power consumption - and, as an extension, performance.

ASRock Industrial ships the 4X4 BOX-7735U/D5 in the 'Normal Mode' with AMD's suggested TDP of 28W. However, a toggle in the BIOS can push the system into a 'Performance Mode' with a souped-up TDP of 42W. This review explores the performance profile of the PC in both modes, and provides detailed insights into the differentiating aspects of AMD's Rembrandt-R in a UCFF mini-PC platform.

Introduction and Product Impressions

Ultra-compact form-factor (UCFF) systems have managed to successfully replace bulky tower desktops for many use-cases over the last decade. The category continues to experience growth in both home consumer and industrial settings. The B2B / industrial computing arms of many motherboard vendors have also started providing more attention to such systems. ASRock Industrial (spun out of ASRock's business unit in 2018) has been creating UCFF systems based on both AMD and Intel platforms since 2019. We have reviewed a number of systems from the company in the last couple of years, ranging from the 4X4 BOX-V1000M (based on the AMD Ryzen Embedded V1605B Zen SoC) to the NUCS BOX-1360P/D4 (based on the Intel Core i7-1360P Raptor Lake-P processor).

This review delves in detail into the company's flagship AMD UCFF offering for 2023 - the 4X4 BOX-7735U/D5. Based on AMD's high-end Rembrandt-R 28W offering (Ryzen 7 7735U), the new system is meant to be a follow-up to the Cezanne-based 4X4 BOX-5800U released last year. The Ryzen 7 7735U continues with the same 8C/16T configuration of the Ryzen 7 5800U. However, the fabrication process has moved from TSMC's 7nm to 6nm FinFET, allowing the Zen 3 microarchitecture to get rebranded as Zen 3+. The process change has resulted in better voltage-frequency curves, with the net result being higher clocks for better performance and improvements in energy efficiency. More importantly, AMD has re-architected the integrated GPU - moving from the Vega-based one in Cezanne to a RDNA2-based Radeon 680M in Rembrandt-R. This has allowed the company to reclaim ground lost to Intel when the latter introduces the new Xe architecture into Tiger Lake and later processors.

ASRock Industrial's UCFF systems are non-descript machines that do not opt for a fancy industrial design. The functional casing used in previous 4X4 BOX systems is retained for the 4X4 BOX-7735U/D5 also. While the Intel-based NUC(S) BOX lineup made the thankful move to matte polycarbonate for the chassis, the 4X4 BOX series continues to retain the glossy fingerprint magnet casing. The I/O port locations are exactly the same as in the previous generation, but the changes in Rembrandt-R has resulted in major updates to the internal board.

The company's 4X4 BOX-7000 series has only two members - one based on the Ryzen 7 7735U and the other based on the Ryzen 5 7535U. Some of the key relevant aspects are brought out in AMD's introductory slide to the product family back at the 2023 CES.

Unlike some of the other rebadges like Barcelo-R, Rembrandt-R supports only DDR5 and LPDDR5. For systems with user-replaceable memory like the 4X4 BOX-7000 series, DDR5 SODIMMs are the only option. The move to PCIe 4.0 means that the M.2 SSD slot on the board becomes capable of supporting Gen 4 SSDs. AMD also promises USB4 in the platform for fast external devices - and, as we shall see later on in this review, ASRock Industrial has configured the board components appropriately to enable this on both Type-C ports in the front panel.

ASRock Industrial offers both barebones version of the system as well as the motherboard alone. The former is typically sold in the retail, while the latter is meant for the B2B channel. The barebones version package comes with a 120W DC power adapter (19V @ 6.32A), VESA mount (and associated screws), a geo-specific power cord, the main unit, and a product overview / user setup guide.

The barebones version needs to DDR5 SODIMMs and a M.2 2280 SSD to complete the build. Kingston offered a DDR5-4800 FURY kit (2x8GB) for the build, and we complemented that with a Samsung PM9A1 512GB Gen 4 NVMe SSD (OEM version of the 980 PRO).

Access to the SODIMM and M.2 slots is via the underside. Removal of the four screws at the bottom allows the panel to be popped off.

While it is possible to install a 2.5" SATA drive in the system, ASRock Industrial strongly recommends not doing it in order to aid with proper airflow. The installation process is otherwise similar to the older 4X4 BOX systems, and we were up and running with a freshly installed OS in no time. Windows online updates resolve almost all of the unknown devices in the device manager, but a few do need the AMD Chipset Driver package from ASRock Industrial's product support page.

The full specifications of the review sample (as tested) are summarized in the table below. As we will note in the next section, the BIOS allows the system to be configured in either of two modes with different TDPs, as specified in the Processor entry.

In the next section, we take a look at the various BIOS options and follow it up with a detailed platform analysis.