QNAP TS-459U-RP Turbo NAS Reviewhardnrg - July 22, 2010
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Testing is not just about performance results. Some of the more practical aspects include operational aspects such as power and cooling.
As the TS-459U-RP is housed in a 1U server rack enclosure, it makes use of three 40 mm fans to pull cool air through the vents at the front, and push air out of the rear vents and towards the rearwardly-exhausting PSU fans. The speed of the three system fans is controlled by the motherboard, and in the System Administration / Hardware section of the WebUI, you can select either a temperature-based fan speed control (Smart Fan), or lock the fan speeds to one of three presets: Low, Medium, or High speed. I found these speed presets to be 2896, 7670, and 10227 rpm respectively.
As I don't have suitable sound level measuring equipment, I'll just say subjectively that, sitting at a distance of 1 m away from the NAS, the low fan speed is muted and easily tolerable, medium is slightly tiresome after a while, and high speed is loud and annoying. During testing, when the NAS kicked the fans into high speed, my girlfriend said "something in the computer room sounds angry!" The annoying thing about the Smart Fan modes is that they can only invoke the low or high fan speeds, so the noise level switches between nicely muted and "angry". I really wish that the NAS could run at medium fan speed under Smart Fan mode, as the high fan speed noise is approaching unbearable, and can be heard from adjacent rooms and even on the floor below. The custom Smart Fan mode only triggers by the system temperature; I would prefer to be have the option to select different component temperatures to trigger the fan speed state, e.g. bumping the fan speed up to medium when one of the hard drives reaches 45°C, and up to high speed when one reaches 50°C. (Please note: this issue seems to have been addressed with firmware v3.3, enabling a variable fan speed rather than a sudden jump to maximum.)
The high fan speed only really kicks in during major RAID operations like an initialisation/format or rebuild/synchronisation. During normal usage, the Smart Fan mode sets the fan speed between the low and medium manual speeds. You could therefore quite safely set the fan control to manual, running at either low or medium, as long as you had a consistent ambient room temperature. After testing, I ended up setting the fan control to manual/low, because it provides ample cooling at a the lowest level of noise, and my computer room is well-ventilated.
However, for the review, I left the fan control set to the default Smart Fan mode that triggers the high fan speed whenever any of the following temperature conditions is true: System >= 57 °C, CPU >= 62 °C, hard drive >= 54 °C. It returns to low fan speed when System < 40 °C.
|Ambient Room||23 °C||23 °C|
|CPU||53 °C||54 °C|
|System||44 °C||45 °C|
|HDD 1||40 °C||42 °C|
|HDD 2||42 °C||44 °C|
|HDD 3||41 °C||43 °C|
|HDD 4||41 °C||42 °C|
|System Fan 1||4720||5232|
|System Fan 2||4753||5192|
|System Fan 3||4720||5192|
Even during intense data access, the temperatures of the components are kept very near to the idling operating temperatures, with only a small increase in fan speed. This is mostly due to the low CPU usage (< 20%) of the NAS during normal usage. The maximum temperatures result from extended heavy CPU usage (> 75%) when RAID arrays are being rebuilt, synchronised, etc. During the most demanding stages of these RAID operations, the Smart Fan kicked into high fan speed when necessary, holding the CPU and hard drive temperatures at steady maximums of 57-62 °C and 44-48 ° C respectively.
One of the major benefits of running a NAS, instead of a computer with shared storage, is the substantially lower power requirements. The TS-459U-RP is an Intel Atom based machine, and offers additional power saving with its ability to suspend hard drives that are not being accessed. You can take the power savings further by scheduling power-on/off states, and enabling the Wake-on-LAN feature, allowing the system to consume a very small amount of power.
A Prodigit Electronics 2000MU Plug-In Power Meter was used to measure the power consumption of the NAS in different states of operation. The 2000MU meter has an accuracy for active power, Watts, of 0.5% typical (2% max).
|On: HDD Idle||75-81|
|On: HDD Sleep||39|
|On: RAID-5 Test||82|
When the TS-459U-RP is in its fully operational powered-on state, the power consumption is already at a relatively low 75-82 W, much less than a typical desktop computer or general-use server with four hard drives. If the use of the NAS is sporadic rather than continuous, you could take advantage of the hard drive power saving modes, to effectively cut the power consumption in half, at just 39 W. You would have to choose wisely however, as a large increase in spin-up/spin-down cycles will reduce the life of your hard drives. For the most power saving, you can use the Wake-on-LAN mode to make the NAS an on-demand server. While the NAS is in its off state, it uses just 5 W, so you could make significant savings if the NAS is not needed for long periods of time.
Given that the maximum power consumption is lower than that of a typical laptop (90 W), and the NAS is running four regular desktop-class hard drives (not "green" or "eco-friendly"), I was quite frankly astounded by the low power usage of the TS-459U-RP.