The ASRock 4X4 BOX-7735U/D5 is an SFF/Mini-PC that certainly packs a hefty punch, considering its small size of 110.0 x 117.5 x 47.85 mm. This is entirely due to the powerful yet energy-efficient AMD Ryzen 7 7735U, which delivers chart-topping performance in our testing suite. While limited to 8c/16t vs. the Intel i7-1360P, which has 12c/16t via a mix of P-cores and E-cores, the Ryzen still proves to be an equal or better performer, especially once you factor in the Radeon 680M integrated graphics. Every other system tested falls far behind, with only the ASRock 4X4 BOX-4800U putting up a decent fight until looking at IGP performance specifically. Keep in mind that is with the CPU configured at its rated 28-watt TDP. Using ASRock's performance mode boosts the TDP higher, letting the CPU further stretch its legs at the cost of increased noise, allowing for an even bigger performance lead. In SPECviewperf 13, the Radeon 680M IGP absolutely dominates the tested competition, with nothing else even coming close. Just make sure to manually set the IGP to use 2 GB of memory, as leaving it on auto will set it to 512 MB and you will see severely reduced performance.

The RDNA 2-based IGP delivers modern features and truly astounding performance, proving to be more than adequate for casual gaming. I was able to easily play Fortnite, The Witcher 3, Total War Warhammer, Fallout 4, and GTA V at 1080p. In Total War Warhammer, I was able to push ultra Settings, while high settings were very comfortable. Meanwhile, The Witcher 3 was able to run at medium settings, with frame rates staying above 30 FPS. The ability to utilize FSR would also likely allow for higher resolutions, although graphical fidelity would suffer in some respects. With this level of performance, casual gaming is easily achievable.

Furthermore, emulating PS2 games proved to be quite easy. Although Metal Gear Solid 3: Snake Eater still had performance hiccups in cutscenes and a few other situations, I got the game itself to run quite well in the early levels. Overall, I am impressed by what this ultra-efficient system can do, especially in performance mode. With a maximum power draw of just 60 watts from the wall, the performance is truly astounding, delivering PS4-level performance. In normal mode, the system peaks at just 40 watts from the wall. Meanwhile, idle power draw was around 10 watts.

While ASRock has not yet confirmed that eGPUs can be used with the 4X4 BOX-7735U/D5 or other systems they manufacture with USB4, our industry colleagues at Tom's Hardware have tested it and confirmed that eGPUs using USB4 will work. While the performance may vary, it is definitely a great option to increase the system's performance further. For example, if you have a thin and light notebook and opted for an eGPU that works with USB4, there is a good chance you can use this system in the home office with the same eGPU, giving you the flexibility of working from home or on the go without compromise and with only one GPU needed for that extra power. It certainly increases the system's versatility; however, ASRock's failure to test or confirm this functionality is a missed marketing opportunity on their part. Also keep in mind that your mileage may vary as I do not currently have an eGPU to confirm how well a configuration of this nature will work first hand.

The only downside to using the performance mode is the increased power draw which peaks at 60 watts under heavy load compared to 40 watts in normal mode and requires the users to set the fan to full speed to guarantee that level of performance. While this does keep temperatures manageable with a peak of 85°C and typical load temps around 70°C, it also results in noise levels peaking at 54 dBA at 15 cm. With the system behind a monitor, I did notice a 5-7 dBA reduction, which improves the user experience. In normal mode, temperatures spike to 92°C and settle around 80°C with noise levels around 45 dBA. In this situation, a better fan profile in the BIOS would work wonders. While the BIOS is overall very limited, ASRock does allow for two performance profiles and some fan profiles, but these fan profiles are not optimal. You can choose between a level and a temperature target. Another missed opportunity is the lack of a system fan curve setup, which would allow for finer control and enable users to get the best of both worlds - quieter operation for light workloads and optimal cooling when pushing the system in heavy tasks. Still, beyond the quick temperature spikes, the system never thermally throttled and instead stuck to its TDP ratings, meaning there is no performance degradation. That said, temperatures could be improved if ASRock implemented better venting to improve airflow to the fan.

Although the price tag of $649.99 for the barebones unit may seem high compared to many competing products, especially when you consider the cost of an SSD and DDR5 SO-DIMM memory, it feels justified. While many SFF systems can offer good CPU performance, GPU performance is always lacking. While the Radeon 680M can't replace a mid to high-tier GPU, it still stands head and shoulders above all other options. Therefore, at $805, as configured at the time of the review, I can't really fault the price. Obviously, shopping for deals on memory, opting for a different SSD, etc., can all lower the price. For example, picking a different M.2 SSD on sale can lower the price by as much as $40. Opting for slightly slower memory, CL40 vs. CL38, can save another $20, dropping the overall system cost by roughly $60. Considering the performance it is capable of, a price tag of around $745 is quite fair, even if it feels expensive compared to many other competing options.

In terms of I/O, the unit does feel lacking when it comes to USB ports. However, a Type-C hub would eliminate this potential issue while still allowing for an eGPU or third display if needed. In the default configuration with no extra adapters, having only 3 Type-A ports feels quite lacking. However, in some situations, this may be made up for via the inclusion of 2 Ethernet ports, one being a 2.5 GbE and the other 1 GbE with DASH. Still, for many users, they will likely want to get a USB hub if they have numerous USB devices they use regularly. Outside of the I/O, overall build quality is good, and since it's barebones, being able to upgrade memory and storage is a plus.

Although the ASRock 4X4 BOX-7735U/D5 may be on the expensive side for an SFF/Mini-PC, and the 1-year warranty feels rather weak, it delivers truly exceptional performance in a tiny form factor along with great versatility with no issues handling nearly any task you can throw at it, making it a system I myself would actually buy.