Will an External Hard Drive Speed Up My Computer?by Russell Huebsch
External hard drives, in addition to giving you more room for files, can speed up your computer in certain circumstances. However, if you purchase an external drive specifically to speed up your system, you will probably be disappointed.
Ideally, you should leave 10 percent to 20 percent of your internal hard drive space free, according to Earthlink Security Center. Using the maximum capacity of your hard drive creates bad portions on the disk and slows down your system.
You should not use an external hard drive as your main drive. Most external drives connect via a USB port, which has maximum effective transfer rates of 40 megabytes per second, while the typical hard drive gets at least 50 megabytes per second, according to EverythingUSB.com.
To maximize hard drive speed, keep files you use often, such as software and your operating system, on your internal disk. Store photos and archived files or other rarely used data on the external disk, according to Earthlink.