External drives will not make your computer do anything faster!
External Hard Drives, or HD, are for backup and or if you need to extend the storage size of your existing computer/device.
If your computer has USB3, it will perform MUCH FASTER than the older USB2 or USB 1.1 or older versions! BUT it will not perform as fast as an internal HD!
Here is the reason: The internal HD has interface called SATA and the data can flow much faster than using the USB port.
USB port has to travel through several components, before the data reaches the internal hardware, that is why it is little slower than SATA interface.
Also, remember to unplug the USB device as soon as you aren't using the external HD, just in case your computer gets a virus!
The virus will spread to every device your computer has a connection to!
In my profession I see too many unhappy people, who did not backup their data to external the HD (Hard Drive) !
Don't bee one of these unhappy people yourself!