|NETGEAR ReadyNAS NV+ v2 NAS Server|
|Reviews - Featured Reviews: Network|
|Written by Bruce Normann|
|Tuesday, 31 July 2012|
Page 4 of 15
Technology Details: NETGEAR ReadyNAS NV+ v2
The biggest chip on the board is not the Marvell ARM-based CPU, but it's still probably the hardest working hunk of silicon inside the chassis. That's because it's the most important IC on the board; it's the system controller, also known as an "Embedded Processor", "System-on-a Chip" (SOC) or just plain old CPU. Back in the day, the CPU was just the CPU, a number cruncher, but we all know that Large Scale Integration waits for no man. Today's "CPU" includes a whole bunch of other support and interface modules that simplify and streamline the system for the twin goals of increasing performance and reducing costs.
NETGEAR uses the Marvell 88F6282 processor, which houses an ARM®v5TE Single Core CPU running at 1.6 GHz, with a 256KB L2 Cache. The memory controller is integrated, and it handles DDR3-1066 or DDR2-800 memory modules. The ReadyNAS NV+ v2 uses DDR3-1333 9-9-9 memory, which is soldered directly to the motherboard. Some of the capabilities go unused on the TS-419P II, like the audio port, but many of the functions are utilized in the design. Although I see a Security Engine in the Marvell block diagram, the ReadyNAS models do not support AES 256-bit volume-based encryption. As slow as the Atom-based models are with encryption enabled, I can't see it being anything but a complete performance killer with the ARM processor.
Marvell supplies several other ICs on the main board; they comprise the two main interfaces: one is for the four SATA devices and the other is the single port Gigabit Ethernet (GbE) controller. The 88SM4140 Serial ATA II Port Multiplier takes advantage of the existing SATA interface on the Marvell 88F6282 CPU, and expands that connection to the four SATA devices sitting in the HDD bays. The device uses adjustable pre-emphasis and amplitude settings on all 5 ports (1 host, 4 devices) for tuning high-speed, long-trace backplane implementations. This is a critical design feature for this application since the chip is mounted to the main board, and not on the backplane, where it would be closer to the drives.
The last of the three major Marvell ICs is the 88E1318, a Gigabit Ethernet PHY controller. PHY is a new acronym for many of us; it refers to a physical transceiver that operates at the physical layer of the OSI network model. Realtek is probably the most popular controller in the PC motherboard world, but Marvell currently produces nine different models of single port Gigabit Ethernet (GbE) controllers in their Alaska product line, so there must be a big enough market for a variety of vendors to survive.
256 MB of DDR3 memory is standard on the ReadyNAS NV+ v2; it's soldered directly to the board, and is not upgradeable. The two chips in my sample were supplied by Hynix and are rated for DDR3-1333 with timings of 9-9-9 for CL-tRCD-tRP. The memory controller built into the Marvell system controller can only access them at DDR3-1066, and the memory chips support that speed as well as a variety of other speeds and timings.
Last, but not least of the major ICs on the controller board is the Flash memory, which is 128 MB of SLC-based NAND sourced from Hynix again. It's actually the largest chip on the board, because the single H27U1G8F2B chip is built with 48nm features, which is ancient technology for the flash memory world. In this application, it's not anything close to a disadvantage; the designer just needed the cheapest part that was going to stay in production for the next couple of years. Serving up a Linux-based operating system to a 1.6 GHz ARM CPU is the dog's life for a flash memory chip; this one never, ever breaks a sweat.
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 ReadyNAS NV+ v2 first boots up, 10 W is consumed at first. Once the system completes its boot process, and gets into idle standby mode, it consumed about 8 watts of electricity. With all four drives installed and during file transfer operations, it drew 47W, which is in line with the published specifications. When the unit is turned off, it still consumes 1W in Vampire mode; be aware that even when it's turned off, the 90W SMPS brick 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 ReadyNAS NV+ v2. The next couple of sections aren't overly 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.