Zotac ZBOX CI321 Fanless Nano PC

Table of Contents

The Zotac ZBOX CI321 Nano is not a speed king with a low speed Haswell-based Celeron processor but its built-in peripherals and fanless chassis make it a compelling budget barebones mini-PC.

April 27, 2015 by Lawrence Lee

Zotac ZBOX CI321 Nano
Barebones Mini PC

A few months back we took a look at the Zotac ZBOX CI540 Nano, a barebones UCFF (ultra compact form factor) system that also happened to be completely silent. This was made possible by using an ultra low voltage dual core Haswell processor, the Core i5-4210Y, and a plastic chassis with considerable ventilation on all sides. Rounding out this mini-PC was a wireless adapter, SD card slot, and consumer IR receiver, all built-in, giving it a varied and unique list of features that set it apart from the competition. The CI540 is part of a stable of passively cooled nettops, the ZBOX C series, which will soon be welcoming a new low cost member, the CI321.

Zotac ZBOX C Series (Barebones) Comparison
Celeron N2930
Celeron 2961Y
Core i3-4020Y
Core i5-4210Y
CPU Clock (Turbo)
4 x 1.83 (2.16 GHz)
2 x 1.1 GHz
4 x 1.0 GHz (1.4 GHz)
2 x 1.5 GHz
2 x 1.5 GHz (1.9 GHz)
Intel HD Graphics
Intel HD Graphics
Radeon HD 8250
Intel HD 4200
Intel HD 4200
GPU Clock
313 ~ 854 MHz
200 ~ 850 MHz
300 ~ 400 MHz
200 ~ 800 MHz
200 ~ 850 MHz
802.11ac + Bluetooth 4.0
2.5″ SATA
1 x 6 Gbps
1 x 3 Gbps
1 x 6 Gbps
Card Reader
3-in-1 (SD/SDHC/SDXC)
Front USB
2 x 2.0
2 x 3.0
2 x 2.0
Rear USB
4 x 3.0
2 x 3.0
1 x 2.0
2 x 3.0
3 x 2.0
4 x 3.0
4 x 3.0
US Street Price (Plus Edition)
$110 ($235)
$140 MSRP
$150 ($260)
$235 ($350)
$290 ($405)

The primary difference between all the available models is the processor, with a Bay Trail-M Celeron in the entry level CI320, a Kabini APU in the CA320, and Haswell chips for the rest, including the CI321. Compared to the Core i3-4020Y and Core i5-4210Y, the Celeron 2961Y is a little stripped down under the hood, equipped with a lower class integrated graphics chip with fewer EUs, only 2MB of cache instead of 3MB, no Hyper-threading, and no Turbo Boost. The latter is particularly unfortunate as the chip has a very modest 1.1 GHz clock speed.

The loss of computing prowess is acceptable when you consider its US$140 MSRP is less than half the going rate for the CI540, and being newer, actually has more features. The latest edition to the C series touts front USB 3.0 ports, a second gigabit ethernet controller, and memory support doubling to 16GB, though the average user probably will only use one of these extras. To complete the system, you’ll need one or two DDR3L (1.35V) SO-DIMMs and a single 2.5 inch SATA drive. It’s simple to add these components but if you can’t be bothered, or want to save a bit on a full copy of Windows, they also offer complete systems. Each model has a corresponding Plus edition that ships with 4GB of RAM and a 64GB SSD with Windows 8.1 pre-installed for US$110~$125 more. Currently there’s no pricing information on the fully configured CI321 Plus, but you can expect to pay a similar premium.

Specifications: Zotac ZBOX CI321 Nano
(from the
product web page
Product Name ZBOX CI321 nano (ZBOX-CI321NANO)
CPU Intel Processor 2961Y (dual-core, 1.1 GHz)
GPU Intel HD Graphics
Memory DDR3L
1600 MHz
2 x 204-pin SODIMM
up to 16GB
Networking 2 x 10/100/1000Mbps
802.11ac + Bluetooth 4.0
Audio Analog Stereo output
Digital 8-ch via HDMI S/PDIF
Storage Hard Drive: 2.5-inch SATA 6.0 Gb/s compatible
Memory Card Reader: 3-in-1 (SD/SDHC/SDXC)
Ports HDMI x 1 (1920×1200 @ 60 Hz)
DisplayPort x 1 (2560×1600 @ 60 Hz)
SATA x 1 (SATA 6.0 Gb/s)
USB 3.0 x 4 (2 front, 2 on back panel)
USB 2.0 x 1 (back panel)
Cooler Passive cooling without cooling fan
Packaging Content 1 x ZOTAC ZBOX CI321
1 x WiFi antenna
1 x VESA mount
4 x Mounting screws
1 x Mini-Optical S/PDIF adapter
1 x AC adapter 1
1 x Power cord
1 x User manual
1 x Warranty card
1 x Quick Install Guide
1 x Driver disc

One thing noticeably absent from the specifications is Consumer IR. For some reason, this is omitted on every member of the ZBOX C family even though it clearly exists. The receiver is visible on the front panel, a working driver for it is provided by Zotac, and it’s even mentioned as a feature in the included pamphlet.

The ZBOX box and the ZBOX itself.


The ZBOX is somewhat larger and taller than the original slim version of the Intel NUC, but it’s still quite petite, about the same size as two standard 120 mm fans stacked atop one another. Included in the package is the requisite power adapter and cable, VESA mounting bracket and screws, wireless antenna, mini-optical S/PDIF adapter, warranty card, manual, and a rather large illustrated fold-out assembly guide/brochure. And while the CI540 shipped with a USB thumb drive containing the necessary drivers for the machine, the cheaper CI321 comes with just a plain driver disc.


The Zotac ZBOX CI321 Nano uses an identical enclosure to the CI540 Nano (and presumably the rest of the C series) with a plastic composition and an open airflow design with plenty of honeycomb vents on the top, bottom and sides. Its dimensions are a mere 12.7 x 12.7 x 4.9 cm or 5.0 x 5.0 x 1.9 inches (W x D x H) and it weighs 570 grams or 1.3 lb in its barebones state.

Featured at the front is the power button, 2 x USB 3.0 connectors, Consumer IR receiver, line-out and mic jacks, and a memory card slot (SD/SDHC/SDXC).

The rear is home to the DC-IN jack, DisplayPort and HDMI ports, twin RJ45 connectors (both gigabit), 2 x USB 3.0 and 1 x USB 2.0 ports, and the WiFi antenna hookup.

Providing power is a simple 19V 40W power brick with a class V efficiency rating.

Similar to the NUC line, four screws that double as chassis feet are used to access the interior.

Visible inside is the mainboard, two DDR3L SO-DIMM slots, an Intel wireless adapter, and the SATA connector and mounting bracket for a 2.5 inch drive.

The system fully assembled with a 4GB stick of Kingston DDR3-1600 memory, and a HyperX 3K 120GB SSD.


System Configuration:

  • Intel Celeron 2961Y processor (embedded) – 1.1 GHz, 22 nm, 11.5W, Intel HD Graphics
  • Delta ADP-40KD DC power supply (included) – 19V, 40W (stock)
  • Kingston ValueRAM SO-DIMM memory – 1x4GB, DDR3-1600, CL11, 1.35V
  • Kingston HyperX 3K
    solid state drive – 2.5-inch, 120GB
  • Microsoft
    Windows 7 Ultimate
    operating system, 64-bit

Test configuration device listing.

Measurement and Analysis Tools

Timed CPU Benchmark Test Details

  • Adobe Photoshop: Image manipulation using a variety of filters, a derivation
    of Driver Heaven’s Photoshop
    Benchmark V3
    (test image resized to 4500×3499).
  • Eset NOD32: In-depth virus scan of a folder containing 32 files of varying
    size with many RAR and ZIP archives.
  • WinRAR: RAR archive creation with a folder containing 68 files of varying
    size (less than 50MB).
  • iTunes: Conversion of an MP3 file to AAC.
  • TMPGEnc Xpress: Encoding a XVID AVI file with VC-1.
  • HandBrake: Encoding a XVID AVI file with H.264.

3D Performance Benchmarks

Testing Procedures

Our main test procedure involves and recording the various temperatures and fan speeds, power consumption, and noise level, with the system in various states as we deemed appropriate. This includes idle, H.264 and Flash playback, video encoding with TMPGEnc, and full CPU and GPU load using Prime95/CPUBurn and FurMark. This is followed by a series of both CPU (timed tests of real-world applications) and GPU-centric (gaming tests and synthetics) benchmarks.

Certain services and features like Superfetch and System Restore are disabled
to prevent them from affecting our results.
We also make note if energy saving features like Cool’n’Quiet and SpeedStep
do not function properly.


Energy Efficiency Comparison (externally powered systems)

The CI321 is one of the greener nettops we’ve tested under light load, idling at 7W and using 12~13W when playing high definition video. The Logic Supply ML210G-10, with its Bay Trail-D Atom J1900, put up identical numbers but keep in mind it uses an mSATA drive, which should give it a natural advantage. The current king is the original Haswell-powered NUC which uses mSATA for storage as well, and lacks some of the extra peripherals found in the CI321.

Having less advanced hardware gives the CI321 a decided power advantage under heavy load. In these tests, the CI321 uses 4~8W less than the CI540, and the difference is even larger versus the Ivy Bridge and Haswell NUC. Video encoding with TMPGEnc pulls just 13W from the wall while the Crysis Demo pushes that figure to 20W.

Thermal Performance

System Measurements (Extended Use)
System State
Avg. Core Temp
HDD Temp
Ext. Temp*
System Power (AC)
MPC-HC H.264 Playback
TMPGEnc Video Encoding
Resident Evil 5 Benchmark
Prime95 + FurMark
*measured at the hottest point on the top of the machine
Ambient temperature: 21°C.

The faster CI540 Nano ran quite hot when stressed and its CPU actually throttled when the integrated graphics chip was also put under load. The CI321 gets quite toasty as well when pushed but its lower power demands allow it stay stable even with Prime95 and FurMark taxing it to its limit. It’s unlikely anyone will ever load the system this hard but it’s nice to know it can operate properly no matter what you throw at it… at least at room temperature.

Boot Performance

For boot performance we record the time required to reach the Windows 7 loading screen (we stop here because this is the point where the speed of the drive becomes a factor). Prior to this test, the BIOS/UEFI is optimized by setting the hard drive recognition and other delays set to minimum, taking care not to disable common functionality like full USB support, POST messages, etc.

The CI321 boots up quite quickly but there’s a slight lag compared to other UCFF PCs with faster processors like the Gigabyte BRIX Pro, Intel NUC, and ZBOX CI540.

Wireless Performance

Our wireless performance test is a simple timed 700MB file transfer both ways to a gigabit-connected desktop on our lab’s network. There’s nothing special about our setup as it consists of basic consumer networking gear.

Equipped with the same Intel Dual Band Wireless-AC 3160 adapter as the CI540, the CI321 offers similar disappointing performance, transferring at about 40 mbps both up and downstream.

Also of note is a bug that crops up when uploading over WiFi: the mouse cursor becomes very laggy when using a wireless USB mouse/trackpad connected to any of the rear USB ports. If the peripheral is connected to the front, this problem goes away, suggesting it’s an interference issue caused by proximity to the antenna.

CPU Performance



While the CI321’s Celeron 2961Y processor is a Haswell chip, it performs fairly poorly against the competition. I expected it to be beaten by the Bay Trail J1900 in the multi-threaded encoding tests as it has half as many of cores, but it also lags behind in Photoshop and NOD32. As it’s unlikely that many users will use such a device for multi-threaded applications, discounting the video encoding tests leaves it trading blows with the J1900 in single-threaded workloads.

GPU Performance

The Celeron 2961Y features Haswell-class Intel HD Graphics with 10 Execution Units and a core clock speed up to 850 MHz. Synthetic results peg its performance between that of the Core i3-3217U and the Pentium G2120 which sounds about right considering the disparity in GPU hardware under the hood.

Its relative performance in real game benchmarks is similar, with the CI321 taking up a middling position among the systems compared. While it doesn’t offer as much gaming prowess as the original NUC or ZBOX CI540, it’s not that important in the grand scheme of things as none of these nettops hit 30 fps, even at the very low screen resolution of 1280×800. Like most PCs this size, playing demanding modern titles will be an arduous experience.


The latest addition to the Zotac’s ZBOX C line extols the same qualities as the rest of the series. Though lacking processing power compared to the Intel NUC counterparts, they are better priced and have extra features that further enhance their value. While we’re more than satisfied with the noise level of the NUC units we’ve examined, completely silent operation is obviously preferable, particularly when being used as a basic desktop replacement in the home where there’s little ambient noise. Wireless connectivity right out of the box is convenient, as is the built-in SD card reader, and the CIR gives HTPC users added remote options. The CI321’s dual core Celeron 2961Y isn’t very fast though, held back by a fairly low clock speed which results in performance closer to that of a desktop Bay Trail chip rather than the Haswell family to which it technically belongs. It takes a bit longer to get things done, but with an SSD, it’s quite responsive for day-to-day operations, and media playback is flawless at 1080p, which is all many users are looking for.

The CI321 offers a few minor upgrades not present in the older members of the family. The front USB ports being updated to the 3.0 standard is probably the most useful improvement for the majority of users, allowing for quicker transfer speeds to/from external devices without having to reach around to the back. The addition of an extra gigabit NIC seems like an odd choice considering how little physical space is available and how few people can/will take advantage of the extra networking capabilities this provides. A second memory slot brings RAM support up to 16GB but this too seems rather pointless in this kind of system, especially this particular model with its cut-rate processor. Excessive RAM is most often required for extensive media editing/rendering and virtual development, neither of which are likely to be performed on a slow consumer machine.

Set for a May release with a MSRP of US$140, the ZBOX CI321 Nano will slightly undercut the US$150 CA320, which shouldn’t be considered at all due to its weak A6-1450 APU. The CI321 should be marginally faster than the Celeron N2930 found in the US$110 CI320, at least in single-threaded applications, but it’s debatable whether this combined with front USB 3.0 is enough to justify the price difference. Compared to competing devices at the same price-point, it looks fairly tough to beat due to its varied feature-set and passive cooling. One competitor to look out for is the MSI Cubi, a new nettop series sporting Intel Broadwell processors. There’s a US$150 model equipped with a Celeron 3205U, which looks like a much stronger contender on paper, along with both mSATA and 2.5 inch SATA options, and WiFi, along with the usual features.

Our thanks to Zotac
for the ZBOX CI321 Nano sample.

The Zotac ZBOX CI321 Nano is recommended by SPCR

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Articles of Related Interest
Logic Supply ML210G-10 Fanless Bay Trail System
Zotac ZBOX CI540 Nano Fanless Barebones Mini-PC
Logic Supply ML400G-50 Fanless m-ITX PC
Habey MITX-6771 Bay Trail Embedded Motherboard
Gigabyte BRIX Pro SFF Powerhouse
AMD Kabini: Athlon 5350 Desktop SoC

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this article in the SPCR Forums.

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