The Zotac ZBOX CI660 nano barebones is a great starting point for anyone looking for a small form factor system that doesn't compromise on processor performance. Compared to the other mini-PCs that have been tested, it offers best-in-class performance with its Intel i7-8550U; then again, that is not hard when the competition typically sticks with processors like the Pentium N5000 or Celeron N3350 and N3450 in such small systems. While they can offer perfectly acceptable performance for light-duty tasks, the Zotac system gives you some serious muscle when you need it. Unlike the lesser mini-PCs, Zotac's allowed for 4K 60 FPS streaming via Steam with the likes of Doom feeling smooth and fluid with good responsiveness, enabling an enjoyable experience from the comforts of my couch.

The only downside is the limited performance of Intel's integrated graphics, which continue to be good enough for productivity, but you certainly won't be doing any serious gaming. That said, performance in general will suffer under heavy loads over time as the passive heatsink becomes saturated by heat, resulting in the CPU thermal throttling. This results in a performance drop; however, the Intel i7-8550U still stays 400–1100 MHz above Intel's specified base frequency—while it cannot maintain the highest boost clocks, it is still delivering better performance than is guaranteed by Intel's 1.8 GHz base clock.

Overall build quality is exceptional with the system being easy to work with in regards to installing or upgrading memory and storage, and completely tearing the system down takes only a few minutes as the internal layout is well thought out. That said, as a barebones system, you are going to need to provide your own storage, system memory, and operating system, which is a negative for some, but at least gives potential buyers the freedom to choose their own parts and software. This means you're not stuck with 32 GB or 64 GB of eMMC storage and 4 GB of system RAM all soldered onboard, as seen in some other mini-PCs. Instead, you can drop in up to 32 GB of DDR4-2133/2400 SODIMM memory and whatever capacity 2.5" SATA SSD, HDD, or SSHD you want.

In Europe, users can pick between the barebones offering or the CI660 nano Plus, which gives users wanting a more complete and ready-to-go system a single 4 GB DDR4 SODIMM along with a 120 GB SSD. Consumers in the United States sadly only have access to the Plus model for $699.99. Still, more budget-conscious consumers can opt for adding another 4 GB memory stick to end up with a quick, efficient, and silent system. In fact, I would consider that the best overall option regarding price to performance regardless of region since it only adds about $40/€40 to the system's cost.

Power consumption is something this system excels at with it pulling a maximum of just 65 watts from the wall under extreme load. More typical tasks see the unit drawing just 30–40 watts depending on load level. In general, the system sips power considering the performance it offers, and that is because of the processor's 25-watt TDP.

In general, pricing and performance per dollar are not a strong suit for the Zotac ZBOX CI660 nano Plus or barebones models. However, concerning build quality, performance, connectivity, and its complete and utter silence, I would still recommend it, but only in specific situations where a system of this nature would make sense over, say, a similarly configured laptop or general-purpose desktop.

Overall, the Zotac ZBOX CI660 nano barebones and Plus are both an exceptional foundation for anyone wanting a high-performance mini-PC. However, for those wanting a good to go system, the Plus model with another 4 GB of memory will likely be the best bet.