Portable hard drives have become an important tool to store data and backup files for a lot of people, there are many areas requiring attention when buy a good quality portable hard drive: Read and write data speed, power supply situation, quality, weight and seismic capacity, firewire and additional value, the following is a detailed analysis for you.
1, speed: The speeds of the hard disk read and write data is very important, when we use the notebook with external hard disk, if the transmission speed is too slow, it will  reduce the notebook battery life. Currently the read speed of 2.5-inch mainstream brand is about 15-25MB / s, write speed is about 8-15MB / s. If we are copy a DVD movie to a 4GB hard drive at 10MB / s write speed, then the mobile will take time-consuming and is about 6 minutes and 40 seconds; if it’s 20MB / s read speeds, to copy a 4GB DVD movie from external hard disk to a mainframe computer hard drive, it takes time about 3 minutes 20 seconds.
The read and write speed of 2.5-inch external hard disk is usually controlled by drive, read and write control chip, USB port type. Under the speed, 2.5-inch notebook hard drives are divided into two types: 4,200 rpm and 5,400 rpm. in order to speed up the read and write speed of hdd, a lot of hard disk drive manufacturers will increase the read and write cache from 2MB to 8MB
Currently on the market the more common 2.5-inch notebook hard drive brand are Hitachi, Seagate, Western Digital, Samsung and so on, so if you want to buy brand external hard disk, you do not have to take much care about hard models.
Relative to the notebook hard drive itself, read and write control chip and the USB port types often determine the highest brand external hard disk read and write speed. For example, it is the same USB 2.0 interface, mobile hard drives, even using the same type of 2.5-inch Hitachi 5400RPM hard drive, one can provide 28MB / S read speed, while the other can only provide 15MB / S reading speed, This is because the difference of the two chips used for components, But as consumers, we have a hard time figuring out what type of chip a external hard disk is used to control over, it is also difficult to distinguish whether a true high-speed USB2.0 ports from the outside, Therefore, if we want to figure out how quickly a branded external hard disk read and write, we should go to the professional IT web site to view the product evaluation data, or bring laptop to test when purchase.
Tip: To find out a external hard disk read and write speed, the best way is to go to the professional IT website see which products, evaluation, or bring laptop to test it when purchasing.
2, power supply: There are a lot of bad desktop motherboard chassis front USB ports vulnerable to power shortages, this will result in external hard disk can not be found in the normal Windows system. In the absence of sufficient power supply to the mobile hard drive will need to conduct an independent power supply, so most of the mobile hard drives are designed DC-IN DC jack to solve this problem.
For notebook, the 2.5-inch USB HDD work, the hard drives and data interface powered by the USB interface. USB interface provides 0.5A current, while the notebook hard drives and operating current of 0.7 ~ 1A, a general data copying is not a problem. if it’s the larger capacity hard drive or move a large file can easily occur insufficient power supply, but if the USB interface to multiple USB devices at the same time, also prone to power supply shortage, resulting in data loss or even damage the hard disk. To enhance power supply, 2.5-inch USB hard drive will generally ranging from PS / 2 port or usb port to take electric power cord. So, when moving large files you need to connect PS / 2 to take electric power cord. (3.5-inch external hard disk usually comes with an external power supply, so basically there is no supply problem. IEEE1394 interface provides maximum 1.5A current, so there is no need external power supply).
3, Quality: There are many so-called branded external hard disk is actually assembled by the dealers themselves, that is, manufacturers are only available to the external hard disk box dealers, distributors get the box and then loaded into the hard drive. The quality of this brand external hard disk can not be guaranteed, and parallel and even repairing the hard disk drive is likely to be profiteers loaded into the external hard disk in the box sold to unwitting consumers.
So if you wish to buy the best external hard disk, the best way is to go online searches under the authority of the media to see if we can find User evaluation report and the teardown of the post-trial evaluation and choose a product that have a certain market for well-known, good reputation.
4, whether it is the thinner the better: In general, the thinner the shell of the external hard disk, its seismic capacity (accidental fall) worse. In order to prevent accidental fall of external hard disk damage, some manufacturers are offering powerful earthquake external hard disk. Many manufacturers claim to be anti-fall 2 meters, in fact, it is simply not a high degree of focus we should be concerned, because a lot of external hard disk products may still be intact when fall from the 5-m or 10 m height, unfortunately, only one or two Good luck only. usually the height of external hard disk accidental fall is about 1 m.
5, firewire: when the USB 2.0 standard has not yet come, USB1.1 standard is very slow, the fastest read and write speed is 1.5MB / s; while the read and write speeds of firewire interface is accessible up to about 50MB / s, so for a long period of time, firewire is a synonym for high-speed transmission. However, after the standard USB2.0 come out, the read and write speeds approaching 60MB / s, firewire port, so at once thrown behind, and almost all computers have USB ports, only a few has a firewire port, so we can not consider hdd using firewire interface models when purchasing external hard disk.
    However, if you are using Apple Computer, firewire will be able to come in handy at this time, and purchase mobile hard drives with firewire interfaces are more appropriate. Overall, the firewire interface is indispensable.
6, the additional value: a lot of brand external hard disk will be a complimentary anti-virus software, personal information management software, one-touch backup software, encryption software, etc. In fact, many do not have any real value, can be exempt from the temptation.
