
QNAP TS-251A
QNAP are always looking at bringing value-add features to the NAS and their newest, the TS-251a is no different. As well as being a NAS (Network Attached Storage), the TS-251a brings DAS (Direct Attached Storage) features to the home user with the introduction of the USB 3.0 QuickAccess port. The QNAP TS-251a is powered by an Intel Celeron N3060 and provides the following key features:
- Great system performance, perfect for centralized administration, file management and backup
- USB QuickAccess for direct file access without needing a network connection
- Supports 4K hardware decoding and 4K H.264 video transcoding
- Outstanding audio and visual experience with the included HDMI output, multi-channel surround sound and media remote control
- Personal karaoke system with Ocean KTV
- Linux Station with virtualized Ubuntu via HDMI output
- A hybrid strategy to virtualization – Virtualization Station and Container Station
- Support for Virtual JBOD (VJBOD)
Ordering P/N | TS-251A-4G / TS-251A-2G |
Processor | 14nm Intel® Celeron® N3060 dual-core 1.6GHz (up to 2.48GHz) |
Hardware Encryption Accleration | AES-NI |
System Memory | TS-251A-4G: 4GB DDR3L (2 x 2GB) TS-251A-2G: 2GB DDR3L (2 x 1GB) |
Maximum Memory | 8GB |
Memory Slot | 2 x SODIMM DDR3L (For dual-DIMM configurations, you must use a pair of identical DDR3L modules.) |
Flash Memory | 4GB, pre-loaded with QTS system |
Drive Type | 2 x 3.5"/2.5" SATA 6Gb/s HDDs/SSDs |
External Ports | 2 x Gigabit RJ45 LAN port 3 x USB 3.0 ports (Front: 1, Rear:2) 1 x USB QuickAccess (USB 3.0 Micro-B; USB cable is not included) 1 x SD Card Reader |
HDMI | 1, max. resolution 3840 x 2160 @ 30Hz |
Audio Input/Output | 3.5mm Microphone Input jack (for dynamic microphone) 3.5mm Line Out jack (for ampliers or speakers) |
LED Indicator | Status/Power, USB, HDD 1, HDD 2 |
Button | Power/Status, USB one-touch-backup, reset |
IR Receiver | Supports QNAP RM-IR002 and MCE-compliant remote controls |
Others | Kensington security slot, system maintenance port |
Dimension | 169 x 102 x 219 mm (HxWxD) |
Weight | Net: 1.28kg Gross: 2.64kg |
Operating Temperature | 0-40˚C |
Noise Level | 18.3 dB (A) Refer to ISO 7779 ; Maximum HDD loaded ; Bystander Position ; Average data from 1 meter in front of operating NAS |
Power Consumption | With 2 x 2TB HDDs: System sleep: 0.72W HDD standby:7.9W In operation:16.2W |
Power | 65W AC power adapter, 100-240V AC |
Fan | 1 x 7cm system fan (12V DC) |
Hardware Features
Processor & RAM
The QNAP TS-251A is powered by a 14nm Intel Celeron dual-core 1.6GHz processor (6W) that supports bursts up to 2.48GHz. The processor also allows for Intel AES-NI hardware-accelerated encryption to be used with minimal impact to system performance.
The test unit we reviewed was a 2GB version but the TS-251A is capable of supporting up to 8GB when 2 x 4GB DDR3L-1600 dual-channel SO-DIMMs are used. Upgrading the memory modules aren’t as easy as the Pro series unfortunately and does require the removal of the HDD cage.
USB QuickAccess
The key feature of the TS-251A is the USB 3.0 QuickAccess interface. It allows you to perform a range of tasks without needing a network connection including the first time configuration and access to shared files. In order to use the QuickAccess, you will first need to source a USB 3.0 A-Male to Micro B-Male or a USB 2.0 Micro B cable. Unfortunately, QNAP do not include this in the box.

QNAP TS-251A QuickAccess Cable Connection – Image courtesy of QNAP
According to QNAP, the QuickAccess Mode will enable users to connect their PC or Mac to quickly access documents and other data stored on the TS-251A. We tested the QuickAccess using the USB 3.0 ports on an iMac (OS X El Capitan) and a Surface Pro 3 (Windows 10).
The QTS management software offers the following 3 access authentication modes for QuickAccess:
- All NAS Users (default) – any user that exists on the TS-251A will have access via their username and password
- Everyone – any user can access the data without needing to authenticate with a username or password
- Selected Users and Groups – Only authorized groups/users on the TS-251A will have access via their username and password

The authentication options for QuickAccess
4K Video Transcoding
The QNAP TS-251A features the latest 8th-generation Intel HD Graphics. This supports 4K H.264 hardware decoding and video transcoding to stream 4K/1080P content on the fly to various formats to be consumed by TVs, portable players, etc…
Software Features
As we’ve reviewed a number of QNAP devices in the past, I won’t go through all the software features again. Have a look through some of our previous reviews for additional information but I’ll briefly touch on a few below.
File Synchronization across devices and clouds
Using the Qsync application you can transform the TS-251A into a private cloud storage server that is safe, has large-capacity and capable of file synchronization. Furthermore, like other cloud storage services, any file you upload to the configured share on the TS-251A will be made available to all the other connected devices. Qsync is a handy tool for travelers or a geographically dispersed workforce. Similarly, as an added layer of security, the centralized configuration allows administrators to remotely erase the Qsync folder on lost devices.
Centralized backup with Backup Sync
Hybrid Backup Sync now supports syncing with a range of cloud service providers with the TS-251A. You can effortlessly synchronize, restore and backup from the following providers from a single app:
- Amazon – Amazon Drive, Amazon S3, Amazon Glacier
- Google Drive
- Dropbox
- Microsoft – OneDrive, Azure, Bing Cloud space
- Yandex Disk
- Box
- Open Stack Swift
- WebDAV

Hybrid Backup
Helpdesk
QNAP now also include a Helpdesk app with QTS. This can be used to simplify the process in requesting technical support or sending in product feedback to QNAP. The Helpdesk app also incorporates a remote support feature that enables QNAP support to remotely connect to the NAS over a 256-bit SSL encrypted connection. Helpdesk can also provide access to a range of support articles that enable the end user to self-serve.

The Helpdesk app
Performance
The QNAP TS-251A test unit was configured as follows:
- RAM – 2GB
- HDD #1 – Crucial 480GB BX200 SSD
- HDD #2 – Crucial 750GB MX300 SSD
Hdparm was used to see how the unit performed with buffered and cached disk read speeds under RAID-0:
[/dev] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 6328 MB in 2.00 seconds = 3164.72 MB/sec Timing buffered disk reads: 514 MB in 3.01 seconds = 171.01 MB/sec [/dev] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 6080 MB in 2.00 seconds = 3040.16 MB/sec Timing buffered disk reads: 510 MB in 3.01 seconds = 169.40 MB/sec [/dev] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 6000 MB in 2.00 seconds = 2999.94 MB/sec Timing buffered disk reads: 528 MB in 3.00 seconds = 175.83 MB/sec [/dev] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 6220 MB in 2.00 seconds = 3110.05 MB/sec Timing buffered disk reads: 524 MB in 3.01 seconds = 174.14 MB/sec
The buffered disk reads seemed a little low so I switched to RAID-1:
[~] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 5460 MB in 2.00 seconds = 2730.16 MB/sec Timing buffered disk reads: 884 MB in 3.01 seconds = 293.82 MB/sec [~] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 5304 MB in 2.00 seconds = 2652.63 MB/sec Timing buffered disk reads: 896 MB in 3.00 seconds = 298.36 MB/sec [~] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 5144 MB in 2.00 seconds = 2572.72 MB/sec Timing buffered disk reads: 898 MB in 3.00 seconds = 299.26 MB/sec [~] # hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 5180 MB in 2.00 seconds = 2590.14 MB/sec Timing buffered disk reads: 896 MB in 3.00 seconds = 298.55 MB/sec
Benchmarks on OS X are performed using Blackmagicdesign’s Disk Speed Test tool. However, the initial results were far from what we were expecting.

Initial QuickAccess performance tests under OS X returned lower than expected results
I contacted QNAP to see if they knew what could be causing the performance issue and was advised that it could be related to using an older version of Qfinder PRO. Sure enough, after downloading the latest version and plugging in the TS-251A via USB, I was prompted to let Qfinder PRO tweak the settings to give optimal performance. Running the benchmark test again, we saw significant improvements across the board:

Running the Disk Speed Test again after updating Qfinder PRO
Running the CrystakDiskMark benchmark under Windows 10 gave us results that were consistent with what we saw on OS X.

Similar performance was noted under Windows 10
Final Thoughts
The consumer NAS market is fairly crowded with multiple products from multiple vendors fighting for supremacy. As a result, QNAP have continuously differentiated themselves from others through innovation and providing value-add functionality such as various QNAP applications including Virtualization Station and Ocean KTV. Likewise, the brand continues to satisfy the base consumer needs of data backup, media sharing and print sharing.
My only disappointment with the QNAP TS-251A was the lack of a USB 3.0 A-Male to Micro B-Male cable. Overall, a great little NAS suitable for a range of tasks. Finally, if you are running a Mac, don’t forget to update Qfinder PRO to the latest version first.
You get only 110 MB/s through usb 3.1 ? It’s not even more than 1Gbe.
No, it’s all USB 3.0 not USB 3.1.