
The Bottom Line
Pros
- 780M Graphics
- DDR5 SO-DIMM
- PCIe Wi-Fi
- USB4
Cons
- Limited USB connectivity
Should you buy it?
AvoidConsiderShortlistBuyIntroduction, Specifications, and Pricing
ASRock's NUCBOX and 4x4BOX have been some of our favorite mini PCs to come through the lab here at TweakTown, with the Meteor Lake 155H platform from Intel being the latest to make its way into our charts. With that, we switch to the latest on the AMD side of things, with ASRock launching the 4x4BOX with 8640U and 8840U SKUs. Sent to us for review was the 8840U model. Of course, this unit is backed by a plethora of connectivity and supports DDR5.
Specifications for the 4x4BOX-8840U give us the AMD Ryzen 7 8840U, an eight-core sixteen-thread processor with a base clock of 3.3GHz and boost upwards of 5.1GHz. The TDP stands at 28w but is configurable from 15w to 30w. DDR5 is the supported memory type; the 4x4box offers two SO-DIMM slots for this. Speeds are supported up to 5600MHz, while capacity can be ramped to 96GB with 48GB modules.
Integrated graphics for the 8840U is the Radeon 780M, which features twelve graphics cores at 2700MHz. This takes us to the expansion for the 4x4BOX, which includes four display outputs, two of which are conventional HDMI outputs, while an additional two are pushed through USB-C. Internally, the 4x4BOX supports dual NVMe drives, one 2280 and one 2242, while the M.2 Wi-Fi slot is also PCIe-based, making it easily upgradeable; from the factory, ASRock has installed a WiFi6E card from Realtek. Wired network connectivity is handled via two Realtek chipsets, one at 2.5Gbe and the other at 1Gbe. Additionally, this unit supports two USB4 ports on the front of the unit and one USB 3.2 Gen2, while two more USB 2.0 ports are available on the rear.
The pricing of the ASRock 4X4BOX-8840U barebone comes in at $599.
Today | 7 days ago | 30 days ago | ||
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$569.99 USD | - | |||
$821.34 CAD | - | |||
* Prices last scanned on 2/15/2025 at 10:17 pm CST - prices may not be accurate, click links above for the latest price. We may earn an affiliate commission from any sales.
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Overview

The 4x4BOX was delivered in its retail packaging, which is the standard setup we find with all ASRock industrial Mini PCs.

The scope of delivery includes the power adapter up top, followed by the VESA plate and hardware. We also have reading materials as well.

The 4X4BOX includes several ports up front, including a 3.5mm headphone jack, one USB-A, and two USB4 ports.

The sides of the unit are both open to vent the system.

Rear I/O includes power input far left, followed by dual USB 2, dual HDMI 2.1, and mixed LAN with one 1Gbe and one 2.5Gbe.

Internally, the lid of the machine acts as a heatsink for the NVMe and SO-DIMM slots. The layout gives us both SO-DIMM slots at the bottom of the image with both the 2242 and 2280 slots up top.
BIOS/UEFI and Software





The 8840U's BIOS is quite basic; it includes the main screen, which offers hardware information, and the advanced menu, which offers a bit of configuration. Options here include CPU and chipset configuration, along with NVMe and USB. The hardware monitor offers a fan speed setting for users wanting to tune the included fan. It also monitors CPU and MB temperatures. The Boot options include three options that can be configured alongside options for boot logo, num-lock, and timeout.
System/CPU Benchmarks
Cinebench
Cinebench is a long-standing render benchmark that Intel and AMD have relied on to highlight their newest platforms during unveilings. The benchmark has two tests: a single-core workload utilizing one thread or 1T and a multi-threaded test using all threads or nT of a tested CPU.

Getting into testing, the 8840U offered a huge bump to AMD Mini PCs. We scored 1809 in single-thread operations.

Multi-thread was even better, the 8840U competing against and even beating the 13900H landing jut short of the Ryzen Z1E in the Legion Go.
BAPCo CrossMark
CrossMark™ is an easy-to-run native cross-platform benchmark that uses real-world application models to measure overall system performance and responsiveness. CrossMark™ supports devices running Windows, iOS, and macOS platforms.

CrossMark finished up at 1737 overall, and this was a touch better than the 6900HX we tested in the GEEKOM AS6.
AIDA64 Memory

The 8840U's memory bandwidth was 72K read, 65K write, and 67K copy. Latency was ridiculously high at 155ns.
Geekbench

Geekbench landed the 8840U at the top of our charts in multi-thread operations with a score of 12812. Single thread did very well too, picking up 2609.

Geekbench GPU picked up 26K in OpenCL, a touch better than the 680M but not quite as good as the Ryzen Z1E or Arc 8 found in the 155H.
PCMark

The PCMark Extended workload once again puts the 8840U on top, slightly better than the 155H Meteor Lake CPU.
3DMark

Moving into 3Dmark, CPU Profile was our first stop. The 8840U was third best here with a 1007 single-threaded and 1936 two-threaded score.

Looking at higher thread counts, the 8840 takes the top spot with a 7035 sixteen-thread score.

Time Spy scored 3058 overall with the 8840U, just a touch under the Z1E and Arc 8 once again.

Last, we have storage testing, which landed an overall 2158 and a bandwidth of 348 MB/s.
Final Thoughts
The 4X4BOX-8840U Mini PC is a fantastic offer from ASRock and showcases quite well how far AMD has come with its mobile CPUs. Case and point, the 8840 is a U series 28w CPU that is beating out 13th Gen and older H and P series CPUs from Intel and really taking Meteor Lake H series head-on. That said, we would definitely love to see the Radeon 780M evolve as it's been around now for two generations, and Intel's Arc 8 has come from nowhere to give Radeon a run for its money with integrated graphics.
Connectivity is where we go next on the 4x4BOX. ASRock outfitted this SKU quite well overall, with two USB4s on the front alongside one superspeed Type-A port. Unfortunately, that's as far as it goes with USB connectivity as the back ports are USB 2.0 only and will likely be eaten up by your keyboard and mouse quite rapidly. We would have loved to see the USB4 ports moved to the back of the unit just for cable management's sake if you were to run both for displays or a dock the additional cabling across the front of the unit can get messy quite quickly.
Further connectivity is quite good for the 4x4BOX, I do enjoy having 2.5Gbe on this unit though I wonder why ASRock didn't spring for dual 2.5Gbe instead of splitting it 1Gbe/2.5Gbe. Wi-Fi on this unit is good, though we aren't huge fans of the Mediatek chipset, but this can be remedied quite easily as the M.2 slot is PCIe-based so any Wi-Fi 7 card should slot in without issue including the BE200 from Intel.
Benchmarks all showed the 8840U top five in our charts, outside of Crossmark. R23 gave us a touch over 8K single thread, making it the best AMD mobile CPU we have tested, even besting the Ryzen Z1E by a thousand points. Geekbench was similar running single thread at a score of 2609, 150 points better than the Z1E. Running through full system benchmarks, PCMark Extended gave us a score of 6905, the best we have seen out of a Mini PC to date, and CrossMark landed at 1737, once again the best AMD mobile CPU we have tested.
Pricing on the ASRock 4x4BOX-8840U comes in at $599 barebones with the market currently wide open for Mini PC, surprisingly we found no other platforms using the Ryzen 7 8840U on Newegg and widening our search further, we find just the ASRock 4x4BOX-7840U from last year and the current 4x4BOX-8640U, both in the $550-600 dollar range.