I realize this may not be something the typical user would ever need to do, but if you ever test transfer speeds for personal or professional reasons, you’ll need a test file of a specific size in order to get an accurate measurement. I often test USB drive, hard drive, smartphone, and even PC to PC file transfer speeds, which I do with a 500MB or 1GB file, depending on the situation.
And you can easily create these test files in Windows using the command line. Here’s how:
Open the Command Prompt by going to Start > Accessories > Command Prompt, or by typing CMD in the Start Menu search field (Windows Vista and 7). In Windows Vista and 7, you’ll need to run Command Prompt as an administrator (right-click Command Prompt, then select Run as administrator).
Once at the Command Prompt, type the following line and press Enter:
fsutil file createnew XXXXXXX YYYYYYY
Where XXXXXXX is the filename and YYYYYYY is the file size in bytes. So, if you needed a 1GB file named Test1GB, you’d type:
fsutil file createnew Test1GB 1073741824
The test file will be created in the folder shown; for example, if C:\Windows\System 32\ is displayed (as it is above), the file will be created in the System 32 subfolder of the Windows folder on the C drive. You can then navigate to the folder using Windows Explorer and move the file to the location you wish.
Since the test file size must be defined as bytes, you’ll need to know the number of bytes in the number of megabytes or gigabytes you wish the test file to be. An easy way to find this information is to use Google. Just type 1 gigabyte into bytes, for example, into a Google search field and you’ll be given the correct number of bytes in a gigabyte: