Hello,
This is actually a common misnomer.
All storage type devices such as USB Flash, SD or SSD drives will be expressed in SI prefixes pre-format, when formatted in use for the operating system the actual number for a formatted capacity will be shown in binary which is less capacity. This uses a (x1000) bytes measurement, not (x1024) bytes as in Dynamic RAM (typically used to speed up the system).
Thus 32GB of storage memory is 32,000,000,000 bytes which equates to 29.8GB. 32GB of Dynamic RAM is actually 32,768,000,000.
This online calculator will show the conversion after it has been formatted for use in the operating system:
http://www.gordonengland.co.uk/conversion/binary.htm
I hope this makes sense. This will hold true for any storage drive. It's simply using a different measurement of "Gigabyte."
Furthermore when transferring more than 4GB's you'll need to format the drive into NTFS:
Please try the following steps in formatting your drive to NTFS.:
First - Open My Computer
Right click on the SDHC drive
Select Properties
Select the Hardware Tab
Select the USB device
Click the Properties button
Select Policies
Select Optimize for Performance
Click OK
Second - Right click on the Drive
Select Format
Select the NTFS format option
Please let me know if it does not resolve your issue or if you have any further questions.