Performance margin

Compared to PCs and servers, the computational performance was noticeable not only in terms of power consumption. At the lower end of the power spectrum, the devices are based on ARM-based embedded processors. Marvel’s Kirkwood CPU, or its successor “Aramda”, is often used. Alone – without peripherals and disks – they are satisfied with a few watts.


Transfer rates


However, the power saver also quickly reach the limits when it comes to maximum transmission power. At best 70 MByte / s wanted in our tests over the cable. As soon as additional work in the form of a RAID-5, -6 or -10 occurs, the real data transmission rate goes down to its knees.


For the performance tests, we first used Intel's Performace Toolkit, which simulates various transfer scenarios. On the other hand, we copied a 50 GB file format, which consisted of a few kByte-sized documents over MByte-large pictures and mp3 files up to gigantic HD videos in the GByte range

The performance of weak hardware at Seagate's Black Amor NAS 440 was the clearest hit. The 12-TB monster - with RAID-5, a good 8 TByte of usable disk space left over - it brings in practice in writing only 12 MByte / s. Until all 8Tbytes sneak over the line, the measured transfer rate at the 50-gigabyte filemix will be almost eight days.


The Buffalo LinkStation Pro Quad is not exactly a speed wonder despite its modern Armada core. Hardly faster than the Seagate NAS, it is also annoying with a slow and slow build-up of the Web front-end.


The Iomega StoreCenter ix - also Marvel-driven - went astray. In practice, in RAID-5 configuration, it achieved a good 20 MByte / s when writing, while reading a little more than 30 MB / s.


In this respect, NAS systems based on atom are significantly more powerful. The dual-core versions D510 and D525 guarantee a noticeably higher computing power, which is particularly noticeable in RAID-5 operation.


Buying advice: Wireless router


However, electricity consumption is noticeably higher. Thus, the Thecus N4200Pro with Atom D525 processor showed a very good performance, which also raked to the limit of GBit Ethernet capacity in RAID-5 configuration. For this, it is also not a cost-observer with 50 watts consumption.


However, this performance is based on an assembly with four fast Seagate Constellation ES panels, each of which consumes approximately 6.5 watts when idle. As long as the NAS does not send the disks, 26 watts are no longer needed.


Of course, one can also argue about how much transmission is actually required. If you only want to listen to music and view pictures and videos, it makes little difference in practice whether the NAS delivers data at 15, 30 or even 100 MB / s.


However, if you copy large amounts of data - such as extensive music or video clips - the data collection becomes quickly nerve-racking. It is also hard to get slow copies when multiple users access the disks at the same time.


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