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Thecus N5550 NAS Network Storage Server E-mail
Reviews - Featured Reviews: Network
Written by Bruce Normann   
Tuesday, 25 September 2012
Table of Contents: Page Index
Thecus N5550 NAS Network Storage Server
Closer Look: Thecus N5550
Insider Details: Thecus N5550
Technology Details: Thecus N5550
Thecus N5550 Features
Hardware Specifications
Software Specifications
NAS Setup and Usage
NAS Testing Methodology
Basic-Disk Test Results
RAID 5 Test Results
Intel NASPT Test Results
Non-Traditional NAS Results
NAS Server Final Thoughts
Thecus N5550 Conclusion

Technology Details: Thecus N5550 NAS Server

The N5550 uses one of the most recently released Intel Atom Dual-Core CPUs based on 32nm fabrication technology, the D2550. Introduced in March of 2012, the D2550 is a cross between the D2500 and D2700 processors, operating at the lower clock frequency of 1.86 GHz, but supporting Hyper-Threading on its two physical cores. The integrated graphics controller runs at the faster clock speed of 640 MHz, which normally wouldn't be important for a NAS, but Thecus allows direct streaming of HD video from the N5550, so it does come in handy. Lastly, the 1MB Intel Smart Cache and the integrated memory controller that supports DDR3-1066 DRAM are both performance enhancing features that are at the forefront of what's available in low power computing these days. With the D2700 going EOL in September of this year, the D2550 is the crown prince of the Atom family at the moment.


The biggest chip on the board is actually not the CPU, it's the SATA interface/ RAID controller chip. Thecus surprised me by using a SATA controller that's ubiquitous in the PC world, but almost never heard from in the NAS environment. Intel's ICH10R is perhaps one of the most widely used RAID controllers in x86 PCs, just because it was attached as the Southbridge to several generations of high-end Intel CPUs since it debuted in 2008. Short of doing a full blown custom ASIC, it's hard to beat the performance of this mainstream solution, which was developed back when the most common way of increasing disk throughput was to RAID several HDDs together. Today's Southbridges (err.... Platform Hub Controllers) are rightly judged more by their ability to squeeze the utmost performance out of the latest SSDs, but the ICH10R served admirably during the transition period between high speed spindles and flash memory. There is a widespread understanding that the ICH10R has an upper limit of about 660 MB/s on its aggregate of SATA interfaces, but that's of no importance when the system's I/O bandwidth is constrained by a pair of Gigabit Ethernet ports on the back panel of the NAS.


The Thecus N5550 is unusual in its support for dedicated display outputs that are driven entirely by the NAS. Intel recently released a new 64-bit driver for multimedia support, and Thecus followed it up with a new Local Display software module that allows direct connection from the NAS to HDTV. It's a real bonus for both administration tasks, and for supporting streaming video and other multimedia, if you decide to use it for content delivery in addition to storage. In order to do that, some extra chips are needed that you typically don't see deployed on a NAS. The Chrontel CH7318C is a high speed HDMI level shifter that converts low-swing AC coupled differential input to an HDMI 1.3 compliant output. The Intel Atom D2550 has an Intel Graphics Media Accelerator 3650 integrated on it that can handle dual displays, but still needs the extra chip to handle HDMI. Despite the graphical inference in the firm's name, the Silicon Image Sil3132 chip just provides an interface from 1x PCIe on the ICH10R Southbridge to the single eSATA port on the rear panel. The Sil3132 supports two eSATA ports, so future models may support dual eSATA connections.


The two Gigabit Ethernet controllers are supplied by Intel and they incorporate both Media Access Control (MAC) and a Physical Layer (PHY) port. Each WG82574L chip supports one Ethernet jack on the rear panel, and connects to the rest of the system by an x1 PCIe Rev. 1.1 interface. There is a 40kB buffer on-board to smooth out data transfers by buffering complete packets before transmitting them. Intel is one of the premier suppliers of NICs to the enterprise market, so it's not a big surprise that many NAS vendors tend to choose their products for implementing integrated GbE interfaces. Renesas Electronics (nee NEC) provides their ubiquitous D720200F1 chip for USB 3.0 duties. I can't remember the last time I saw any other chip being used for USB 3.0. Sound duties are supported by a Realtek ALC262, a basic soundcard chip that doesn't have a whole lot to do here, except when using the NAS as a multimedia streaming device. Only 2-channel audio is supported here, nothing like 5.1 or 7.1 is available, if you need the full home theater experience.


2 GB of DDR3-1066 memory is standard on the Thecus N5550; it's carried on the SO-DIMM form factor and is addressed by the CPU in Single-Channel mode. The Atom D2550 CPU can support up to 4 GB of DRAM, but it's unclear if the N5550 can support a memory upgrade or not. There are two SO-DIMM sockets on the motherboard and only one module supplied, but the BIOS is the key as to whether an upgrade will work or not. The single SO-DIMM in my sample was supplied by Transcend and is rated for DDR3-1333 with timings of 9-9-9 for CL-tRCD-tRP. The eight SDRAM chips themselves are from SpecTek, which is a division of Micron Technology.


Last, but not least is the Flash memory implemented as a Disk-On-Module (DOM) device, which is 1 GB of SLC-based NAND sourced from local Taiwanese manufacturer Afaya. Serving up a Linux-based operating system to a 1.86 GHz Atom CPU is the dog's life for a flash memory chip; this module never breaks a sweat. Right next to the DOM location is an empty mini-PCI Express slot. No word from Thecus on what it's typically used for, but the most common devices available in that form factor are SSD modules and wireless Ethernet cards. I'd love to see something similar to Intel's Smart Response Technology implemented in a NAS; that's something that more and more high-end storage vendors are starting to roll out in their data center-class storage systems. Virtualized server infrastructures are pushing the storage systems harder and harder, every year. OTOH, a Wi-Fi module is a whole lot easier to implement on this Intel Atom platform, so that's probably what this slot will get used for, first.


To measure isolated NAS power consumption, Benchmark Reviews uses the Kill-A-Watt EZ (model P4460) power meter made by P3 International. Obviously, power consumption is going to depend heavily on the number and type of drives that are installed. The power draw also depends on the fan speed that's required to keep the drives cool. When the Thecus N5550 first boots up, it peaked briefly at 120 W, and then ramped down to a narrow range of 48 W to 54 W. Once the system completes its boot process, and gets into normal operating mode, it settled in at about 53 watts of power consumption. With all four drives installed and during Write operations, it drew 58W; Read operations drew hardly more than idle. When the ½ hour sleep timer kicked in and the drives were powered down, the power consumption went down to 33W. When the unit is turned off, it still consumes 2W in Vampire mode; be aware that even when it's turned off, the integral 200W SMPS still pulls a small amount of power.

We've seen the ins and outs of the hardware, and the technology under the hood; now let's take a quick look through the list of features that you get with the Thecus N5550. The next couple of sections are kind of long, but it's critical to understand what features you get with these units, and what you don't. It's not just a box full of drives; it's capable of more than that.



# RE: Thecus N5550 NAS Network Storage ServerMoogle Stiltzkin 2012-09-25 04:16
honestly... when will these NAS brands ever release a product which has ZFS in it. I am sick and tired of these crappy spec NAS, that can't offer the greatness that ZFS offers such as....

1. deduplication
2. end-to-end check sum error correction (CERN has stated officially, ZFS is the only reliable solution to protect data from bit rot)
3. and other ZFS features

also whats with 2gb minimum ram. they act as if ram is expensive, it's not. these days ram is sickeningly cheap because the companies producing them were not long ago fined for price fixing. Makes me wonder whether NAS companies are purposely price fixing to over charge for devices with little ram to squeeze as much more profit margin ....

People are starting to get fed up and moving onto DIY NAS solutions and which is cheaper, and has ZFS.
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# We Just Did....Bruce 2012-12-07 11:03
We just reviewed that NAS I was talking about. Check out the EonNAS 1100 review on the front page.
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# ZFSBruce 2012-09-25 09:02
I know at least one manufacturer who has brought ZFS into their mainstream product line, and I've reached out to them, to get a unit for review.
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# SynologyFAbio 2012-09-25 09:44
You should review Synology NAS products, too. They are awesome!
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# RE: SynologyOlin Coles 2012-09-25 09:47
We have reviewed several Synology products, but when one product did not receive an award they no longer offered samples to us for testing. Maybe that's why you think they're so awesome?
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# RE: RE: SynologyFAbio 2012-09-25 10:01
They had problems with some products in the past. But recently I bought the model 1812+ and I am glad with his features and behavior. It has basicly the same features that thecus.
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# RE: RE: RE: SynologyOlin Coles 2012-09-25 10:05
I was very disappointed when they decided to stop supporting us with reviews samples a few years back just because one product didn't receive an award. Hopefully they'll change their minds and want to show off their new hardware. QNAP is one particular brand I've seen good things from, and they continue to impress.
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# N5550 Graphic and Memory MALFUNCTION - BE AWAREYaron 2012-09-27 23:46
One thing you should know before even considering this NAS.
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# Only affects memory "Upgrade"....Bruce 2012-09-30 21:04
The manufacturer did not, and does not offer an authorized upgrade of the memory from the standard 2GB. If you change the memory configuration on your own, it might work, and it might not. Don't worry, someone will figure out a way to make it work, and share it on the forum.
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# RE: Thecus N5550 NAS Network Storage ServerYaron 2012-09-30 22:07
I own few Thecus units of different modules.
None of them ever had a problem after upgrading the memory.
This one DOES & for a very specific problem that Thecus CAN'T SOLVE & MIGHT NEVER BE SOLVED.
See the forum for more details...
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# RE: Thecus N5550 NAS Network Storage ServerCarlie Coats 2012-10-02 09:03
I'd like to see ATA-over-Ethernet (AoE), in addition
to SMB, NFS -- much better latency, better security
since it's a UDP (not IP) protocol (confined to the
local network).
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# Thecus one day - Thecus no way!Souldream 2012-10-11 21:31
Forget about buying Thecus NAS.

They have the lowest level of support i have ever seen.

If you plan to buy NAS to put non important files = you can go.

If you plan to buy it for your company to store file, i will not let go ... as you could loose your job LoL

They do the same for 4100 model , low memory = unstable , web manager slow , and Raid destruction ( no hardware raid controller LoL ).

Look over my post in the official forum, and you will understand why Thecus is good on paper , in real use this is nightmare !

You are warned !
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# RUN!!!Tracey 2012-11-08 08:32
As the above post states.. stay far away from this device. Unless you want an Enterprise device that can't copy files to and from without crashing or falsely reporting drive failures. I definitely regret this purchase!

You have been warned... again!
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# 111MB/s is IMPOSSIBLEscavenger 2012-11-28 14:10
I'm using 5x2GB dreives in RAID5.
With ATTO i can have the same results as you have, BUT :
in real life, everybody is using samba shares under windows.

what about the only 55-65MB/s file transfers I get this way ?
Did you do this test ?
How can you show 111MB of read/write as it's impossible to achieve ?
I cannot get 111MB/s with any of the protocols available : smb, ftp, sftp, ssh, nfs, afp.
Please, tell me the truth about your tests ?
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# Yes, it's possibleBruce 2012-11-28 18:22
I assume you just read the Conclusions page, where I stated:
"During timed transfers of 1GB and 10GB files the N5550 recorded Read speeds of 111 MB/s and Write speeds above 118 MB/s. These are the RAID 5 results..."

Go back and read the NAS Testing Methodology page, where I explain how each test is run. The timed file transfers are done in Windows Explorer, of all things. Imagine that...Windows is faster than some dedicated file transfer protocols!

If you can get 120+ MB/s using ATTO, just like I did, then you already know that your unit is capable of that level of performance. So, look at all the extra elements that might be holding transfer rates back in your application(s). Also look at the host computers doing your transfers. I'm using a 10GB RAMDisk to eliminate any potential slowdowns due to the impact of storage devices on my test bed system. Transfer rates from a laptop HDD are going to be MUCH slower, for instance.
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# Oh really :-)scavenger 2012-11-29 14:54
Well I didn't understood you were transferring files on Windows Explorer with mounted SMB shares, exactly the same way I do my tests...
I got the same n5550 with 5x2TB HDD RAID5, and the same RAM disk drive, the difference is my Windows XP 64, and the fact I test with 802.3ad and 2xCAT5 cables on both sides.

I unfortunately am unable to reproduce your tests :
- which switch are you using ?
- which MTU is set on the PC ? on the NAS ? on the switch ?
- which strip size is set on your ext4 FS ?
- can you provide the result of "hdparm -tT /dev/md0" on the NAS ?
- did you "sync" the PC and the NAS after a transfer to eliminate the disk cache smoothing ? (I'm using a ported GNU version of sync.exe)
- did you monitor the RAM usage on the NAS during transfers ? I can get a 2GB peak during heavy load...

None of the time I did achieved a 110MB/s transfer with a single file, the max I get is 82MB/s with 2 files at a time from PC to NAS.
On normal conditions, I get 50-65MB/s max, mostly the same as on the n5500.
Thanks anyway for your time :-)
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# Use Win7Bruce 2012-11-29 17:56
Well that explains it. You will never get the results I get if you continue to use Windows XP. In the "Testing Methodology" section, I reference the comparison I did two years ago between XP and Win7.

"...We are continuing our NAS testing with the exclusive use of Windows 7 as the testing platform for the host system. The performance differences between Win7 and XP are huge, as we documented in our QNAP TS-259 Pro review. The adoption rate for Win 7 has been very high, and Benchmark Reviews has been using Win 7 in all of our other testing for some time now. It was definitely time to make the jump for NAS products. ..." Here's the link:

Win7 beats XP by a mile in these scenarios, you should try it. None of the other factors you mention will make as big a difference as using Win7 on the PC side.
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# LACP BenefitBruce 2012-11-29 19:55
BTW, what improvement in transfer speed are you seeing with IEEE 802.3ad (LACP)?
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# LACP Benefitscavenger 2012-11-30 11:50
Absolutely none, now that I finally understood it's not a load balancing protocol but just a failover one.
But since I invested in a L2 switch + 2 x cables between PC NAS I'm not throwing them away :-)
For the real load balancing one, one have to select balance-SLB + round robin, but it's charging the network for nothing since the packets are not ordered and the final bandwidth is not what I expected :-(
Well with this network configuration, I can have at best 90MB/s but only with 3 file transfers at a time, which is not I wanted.
I want as you have, a 110MB/s bandwidth with a single file transfer.
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# RE: Thecus N5550 NAS Network Storage Serveraceggroll 2013-02-13 18:06
The features I'd like to see are:
  • a USB 3 device (not host) connection (5GBit/Sec max), and

Surely this would be a cost effective way of increasing data transfer between computer and dedicated external storage. (And yes, I know this is not a NAS at this point, but I need a solution to replace a single external Harddrive for a laptop, and USB is a far simpler & cheaper setup than a network connection.)

Are there any vendors that are offering this in the SOHO market?
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# USB, Yes. SATA III, No.Bruce 2013-02-13 18:34
Thecus has upgraded the front USB port to 3.0 specs on the N5550, and many other products. But it's not a "Device" connection, like you are looking for. Does your laptop have an eSATA port? There are several "boxes" available that have 1-4 drive bays and will run pretty well off eSATA, in Port Multiplier mode.

SATA III has a very minor impact on HDD performance, in my experience. It's only when you get to the third generation of SSDs, that SATA III was really needed.
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# RE: Thecus N5550 NAS Network Storage Serveraceggroll 2013-02-13 21:22
Bruce, thanks for tip.

Laptop does have eSATA (1 x eSATA/USB 2.0 combo), but manufacturer doesn't give away how fast the eSATA is going to run :-(

I'm not sure if I'm interpreting the N5550 spec correctly, but the eSATA spec seems to be imply that I would use if for adding an external disk to the device. I want to be able to use the NAS as eSATA storage for a computer/laptop.

If anyone has tried this with other NAS devices, I'd be very interested to know how transfer rates compare between eSATA and GB LAN (as the LAN connection should no longer be the bottleneck.)

Also, if vendors are monitoring this thread... Would be great if you are not then could publish your noise spec. Pretty important if the device isn't sitting in a rack, and next to or on somebody's desk.
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# Not a NAS, per se.....Bruce 2013-02-14 10:01
Yes, all the other interfaces, besides Ethernet, are going to be host connections. It's very rare that any NAS unit would have the capability of multiple "device" interfaces. One that DOES, is the IOCELL NetDISK 351UNE Network Storage Device, which I reviewed here:
It only supports one drive, though.

The drive enclosures that have just USB 3.0 and eSATA interfaces tend to be a whole lot cheaper than a full-blown NAS solution. There are dozens of them at Newegg, like this one:

eSATA itself is a pretty quick interface.
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# RE: Thecus N5550 NAS Network Storage ServerYaron 2013-02-13 22:15
The N5550 can't be a USB target - it can be used only as USB host.
Thecus has the N5200 family which is a bit "older" and I remember one of it's products can do it.
Take a look at their site.
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# Product EvolutionBruce 2013-02-14 10:25
Yes, the N5200 had it: USB ports 2 x USB A type (Host mode); 1 x USB B type (Client mode) .

As others have mentioned, Thecus did a major architecture update on their product line a few years ago. I can't find any instances of Client mode USB in their current offerings.
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# RE: Thecus N5550 NAS Network Storage ServerYaron 2013-02-14 20:24
Right - it doesn't exist anymore.
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# 8 gig ram installed on N5550Bruce MacDonald 2013-03-26 22:36
I just bought this unit last week and have it running on 8 gig of ram I took out of a 2011 MacBook Pro. I edited the menu.lst file via SSH to remove the 4 Gig Ram limitation soft coded. Surprising because Intel lists this processor as only supporting 4 Gig too.

To edit the menu.lst file to remove the MEM=4G parameter

Via telnet/ssh (or console) :

# mount /dev/sdaaa1 /boot
# vi /boot/boot/grub/menu.lst
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# RE: Thecus N5550 NAS Network Storage ServerYaron 2013-09-03 13:25
R U using 1x8g or 2x4g ?
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