Zotac ZBOX CA320 nano PLUS Review: A Fanless AMD mini-PC

HTPC Credentials

The absence of any moving parts inside the ZBOX CA320 nano enables a completely silent PC irrespective of the workload. This makes it an ideal HTPC. While acoustics form one part of the HTPC story, there are a few other aspects that we will cover in this section.

Refresh Rate Accurancy

AMD and NVIDIA have historically been able to provide fine-grained control over display refresh rates. The default rates are also quite accurate. Intel used to have an issue with 23 Hz (23.976 Hz, to be more accurate) support, but that was resolved with the introduction of Haswell. As expected, the Zotac ZBOX CA320 nano has no trouble with refreshing the display appropriately in the 23 Hz setting. In fact, the accuracy is much more compared to what we have been used to seeing in AMD-based PCs and AMD GPUs over the last few years.

The gallery below presents some of the other refresh rates that we tested out. The first statistic in madVR's OSD indicates the display refresh rate.

Network Streaming Efficiency

Evaluation of OTT playback efficiency was done by playing back our standard YouTube test stream and five minutes from our standard Netflix test title. Using HTML5, the YouTube stream plays back a 720p encoding, while Adobe Flash delivers a 1080p stream. Note that only NVIDIA exposes GPU and VPU loads separately. Both Intel and AMD bundle the decoder load along with the GPU load. The following two graphs show the power consumption at the wall for playback of the HTML5 stream and the Adobe Flash stream in Mozilla Firefox v33.1.1 using Adobe Flash 15.0.0.223 and AMD Catalyst 14.9 drivers. OTT streaming doesn't seem to be as efficient as what we had in the ECS LIVA and the GIGABYTE BXBT-1900. While the HTML5 stream had an average GPU load of 37.68%, the Flash stream loaded it to only 28.44%. 

Netflix streaming evaluation was done using the Windows 8.1 Netflix app. Manual stream selection is available (Ctrl-Alt-Shift-S) and debug information / statistics can also be viewed (Ctrl-Alt-Shift-D). Statistics collected for the YouTube streaming experiment were also collected here. The average GPU load was around 17%.

Decoding and Rendering Benchmarks

The specifications of the A6-1450 APU make is very clear that the HTPC is not meant for usage with madVR. In order to evaluate local file playback, we concentrated on EVR-CP (using MPC-HC v1.7.7) and Kodi (v 14.0-b5). We already know that EVR works quite well even with the Intel IGP for our test streams. The decoder used was LAV Filters v0.63.0 (default configuration) bundled with MPC-HC v1.7.7. We left the video playback settings at default (using DXVA2) in Kodi also.

One of the unfortunate aspects was that the interlaced streams caused too much loading on the GPU and the frame drops during playback was quite obvious. On the other hand, the 1080p60 stream, despite being light on the GPU had stuttered playback, enough to be unwatchable. 4K decoding is not supported by the Temash GPU and the CPU is not strong enough to support software decoding. The 4Kp30 playback was a slideshow. On the other hand, things were a little bit better with Kodi (though deinterlacing wasn't perfect for some streams). Frame drops during playback for the interlaced streams, if any, were not discernible. However, the issues seen with EVR-CP / DXVA2 decoding for the 1080p60 and 4Kp30 streams were also seen in Kodi.