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Buffalo Boosts External Hard Drive Power
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1. Power Booster Replaces The Power Supply

External USB hard drives are the easiest way of taking your data with you. Unfortunately, many products restrict mobility because they require a large, bulky external power supply unit. Buffalo now offers a product that solves this problem with a much more elegant idea for powering its drives.

The obligatory external power supply is pretty much a necessity for external storage based on 3.5" hard drives, because those drives have a power draw that exceeds the 2.5 W that USB 2.0 can provide (500 mA at 5 V). Compact hard drives, however, do not necessarily require such high current. Many 2.5" external products can be powered by USB ; certainly, all 1.8" and 1" external hard drives can work without supplemental power.

Still, compact hard drives do not suit everybody’s requirements. Smaller disk platters mean less power is needed, but less storage is also provided. 1" hard drives are available at capacities of up to 8 GB ; 1.8" models store up to 60 GB ; and 2.5" drives feature capacities of up to 160 GB today. In the case of 2.5" drives, this is quite a bit of storage space, but it is far from the 500 GB of modern high-end 3.5" hard drives.

If maximum capacity isn’t your primary goal, then it is much easier to focus on mobility. We believe that 2.5" models are the best choice here, because they combine excellent performance and fairly high capacity. 1.8" drives are a bit smaller and lighter, but storage capacity and data transfer performance clearly suffer as a result.

Even if you go the 2.5" route, you would still be wise get a separate power supply unit if you want to be entirely sure that your hard drive operates with all USB host controllers. You’ll quickly notice that it is rather bulky and heavy, and this will cause you to stop carrying it, because you’ll usually not need it. Then, some day you will urgently need to use it on a particular machine and find it doesn’t work without external power.

Buffalo has a better idea. The company’s approach involves a simple buffer unit that is inserted between the external hard drive and the USB port.

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2. Buffalo USB 2.0 Portable Hard Drive

The Buffalo hard drive looks similar to other external hard drive products. The design is straight-forward, based on a rather simple, black plastic enclosure. It carries an ATA-to-USB bridge as well as a modern hard drive, the manufacturer of which may vary based on what Buffalo has available.

We found a Samsung MP0402H in our 40 GB test sample, which carries the product name HD-PH40U2. We liked the fact that the package tells you the speed of the hard disk, which is a 5,400 RPM model ; these work clearly faster than other models at slower rotation speeds. Although USB 2.0 usually does not allow net transfer rates of above 30 MB/s, a fast hard drive helps sustain high transfer rates, while minimum transfer rates remain acceptable.

There are only two interface connectors on the unit : one mini USB connector and a power connector. As you can see, while Buffalo avoids the requirement for a power supply, the jack is still there if you want or need it.

The drive weighs approximately 5.3 oz, while the Power Booster is another 1.8 oz, and the USB cable a further 1.2 oz. Altogether it is about half a pound, which is still an acceptable total for a portable hard drive product.

3. The Power Booster


Power Booster is Buffalo’s name for the little auxiliary power box that comes with the external hard drive. Think of it as a kind of "mini UPS". Both the input and output USB cables are integrated into the device and cannot be removed. The box is plugged between the computer’s USB port and the external hard drive, and helps to ensure adequate power supply to the drive. Should your USB port be incapable of supplying enough peak current for spinning up the hard drive, the Power Booster comes into action.

It will start buffering energy from the USB connection into a built-in battery as soon as it is plugged to an active computer system (powered on or in standby). It also terminates power to the drive until it is sufficiently charged for the hard drive to start. This took only few seconds with our test system, as the USB port obviously was capable of powering the drive itself. As soon as the drive is powered up, the Power Booster will only keep charging its own battery.

4. Test Setup
System Hardware
Processor(s) AMD Athlon 64 X2 3800+
2.0 GHz, 512 kB L2 Cache (Manchester core)
Platform Gigabyte GA-K8NXP-SLI, Rev. 1.02
Nvidia nForce4 SLI chipset
RAM Crucial Ballistix DDR-400 (BL2KIT6464Z402)
2x 512 MB, CL2-2-2-6 Timings
System Hard Drive Seagate Barracuda ATA 7200. (ST316027AS)
160 GB, 7,200 RPM, 8 MB Cache, Serial ATA II
Mass Storage Controller(s) Integrated nForce4 SATAII & UltraATA/133
Integrated nForce4 USB 2.0 Host Controller
Test Hard Drive(s) Mvix MV-5000U & Maxtor DiamondMax 10, 300 GB
Networking nForce4 on-chip Gigabit Ethernet NIC
Graphics Card Nvidia GeForce 7800 GT, PCI Express, 256 MB GDDR3
System Software & Drivers
OS Microsoft Windows XP Professional 5.1.2600, Service Pack 2
Platform Driver Nvidia Forceware 6.70
Graphics Driver Nvidia Forceware 81.85

Benchmark Results

Data Transfer Diagram

5. Data Transfer Rates

6. Access Time

7. Conclusion

The performance data shows that the performance of the Buffalo hard drive is about average for products in its segment. We measured a steady 21 ms average access time, and a lively 29 MB/s maximum read data transfer rate. The numbers go down a bit when writing, but this is normal for most magnetic media. Altogether, the performance is not ground-breaking, but solid enough for most applications. Remember of course that we are talking about a device whose primary goal is data mobility ; this cannot go hand in hand with the very highest performance.

The Power Booster is a tool designed to make this hard drive a truly portable storage product. Although USB’s 2.5 W maximum power is usually enough to operate a 2.5" hard drive, it is not necessarily enough to satisfy the spin up peak power demands of the hard drive spindle. The Power Booster helps to manage this in an effective way.

However, we have to wonder why Buffalo decided to offer the Power Booster functionality through the additional module. It is obvious that the hard drive itself can also be powered by a conventional PSU, and thus could be sold as a different product as well. Despite this, we would have preferred if the Power Booster was integrated with the hard drive enclosure. This would eliminate the need for an additional module, and reduce the weight and volume of the resulting product. And in the end, isn’t compactness what a highly mobile product should be about ?

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