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Thecus TopTower N6850 review

Our Rating :
Price when reviewed : £795
inc VAT

It’s fast and relatively inexpensive, but the NAS is compromised by noise and a poor interface


6 disk bays, N/A storage supplied, 2x 10/100/1000Mbit/s Ethernet ports

If you don’t have a rack cabinet but still need masses of shared storage, high capacity free-standing NAS devices have obvious appeal. The Thecus TopTower N6850 is a powerful and competitively priced six-bay NAS enclosure with a dual-core 2.6GHz Intel Pentium G620 processor and 2GB of DDR3 RAM. Unlike most NAS devices, the N6850 is upgradeable, having two PCI-E slots that can be used to install expansion cards, such as ultra-fast 10GbE networking cards.

Thecus TopTower N6850

The N6850 has two USB2, two USB3 and one eSATA port on its back-panel, alongside a serial connection port and two LAN ports. It also has a HDMI port, and if you attach a keyboard and mouse you can control the NAS directly rather than access it via its web interface. It has another two USB2 and two USB3 ports at the front of the device and an LCD status screen with touch buttons.

Fitting our hard disks was simple. Small strips of rubber on the drive trays provide a degree of vibration damping, but we were surprised by the relatively loose fit of our drives within the trays. Unfortunately, the NAS is rather noisy in operation. Disk access sounds could be heard and the fans are surprisingly loud, which isn’t ideal for a NAS that might be kept in a main office.

Thecus TopTower N6850

The web interface could be a little confusing for anyone who’s not set up a NAS before, especially because of the poor quality of the GUI’s in-line help. Fortunately, getting the N6850 up and running is a simple process. All you have to do is click the Storage tab and then the RAID management icon in the tree that opens below it. Create your RAID array and you’re ready to go. The N6850’s RAID options are 0, 1, 5, 6, 10, 50 and JBOD.

We tested the NAS using six 4TB Western Digital RE enterprise drives, and ran tests in multiple RAID configurations, including RAID5, RAID10 and RAID50. We tested input and output speed on each type of array configured as both SMB shared folders and iSCSI targets.

In our array of six 4TB drives, RAID5 provides the greatest capacity (18,617.5GB) and the fastest speeds, averaging a throughput of 11.7MB/s in our large-file SMB test, 21.6MB/s in a small-file SMB test, and averaging 114MB/s and 37.3MB/s respectively in our large and small file iSCSI tests. However, RAID5 is less fault-tolerant than RAID10 or RAID50. It can only afford to lose one drive from the array, while both RAID50 and RAID10 can lose up to one disk from each sub-array, which means a loss of up to two disks could be sustained, depending on which disks fail.

Thecus TopTower N6850

RAID10 gives you just 11,171GB across six disks and produced slightly slower throughput in our SMB tests, with large- and small-file average of 94.9MB/s and 21.5MB/s. Our iSCSI tests produced a large average of 103.7MB/s and a small average throughput of 51.2MB/s – the fastest we saw in any of our tests on this NAS. RAID50 is the sweet spot between redundancy, throughput and capacity. You get 14,894GB of storage and SMB average throughputs of 100MB/s for large and 22.2MB/s for small files. iSCSI throughputs average 112.6MB/s and 41.22MB/s.

Once you’ve selected your RAID type, you’ll also be given the option of encrypting your volume. The N6850 has enough power to do this without a significant impact on performance, but it’s only worth doing if the NAS is going to be storing highly sensitive data. You can also set the volume you’re creating as the Master RAID array – this is only relevant if you plan on having more than one RAID volume in the NAS. A Quick RAID option means you won’t have to wait ages while the NAS carries out a low level scan and initialisation of the drives, although this is only intended for use with brand new disks.

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Basic Specifications

Price £795
Rating ***


Capacity N/A
Formatted capacity N/A
Default file system ext4
Price per gigabyte N/A
Interface SATA2
3.5in drive bays 6
Free 3.5in drive bays 6
RAID modes JBOD, RAID 0, RAID 1, RAID 5, RAID 5 + hot spare, RAID 6, RAID 10, RAID 50


Ethernet ports 2
USB direct access ports (front/rear) 0/0
Other USB ports (front/rear) 4/4
eSATA ports (front/rear) 0/0
Other ports HDMI, serial, 3.5mm mic in, 3.5mm line in, 3.5mm line out


Ethernet connection speed 10/100/1000Mbit/s
Universal Plug and Play support yes
UPnP media server yes
iTunes yes
Print server yes
USB disk server yes
Web server yes
FTP server yes
Protocols supported TCP/IP, SMB/CIFS, AFP, FTP, HTTP, HTTPS, NFS, SSH, Telnet, WebDAV, iSCSI


Size 320x215x283mm
Vertical positioning no
Ethernet cable included yes
Additional features load balancing, failover
Power consumption active 111W

Buying Information

Price £795
Warranty five years RTB

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