The PGP Whole Disk Encryption feature offers two options that you can select prior to protecting your disk or partition:
Maximum CPU Usage. This is the fastest way to perform initial encryption on your disk using PGP Whole Disk Encryption, yet it is just as safe. This extra speed comes primarily by taking priority over other operations that your computer is performing. Consider this option for a time when you are away from your computer.
Power Failure Safety. While you can pause the initial encryption process at any time by properly shutting down or restarting your computer, it is exceptionally important to avoid unexpected shutdowns (power failures, power cord gets pulled out, and so on). If this is a possibility for you or if you do not have an uninterruptible power supply for your computer consider choosing the Power Failure Safety option. When Power Failure Safety is selected, encrypting is journaled; if the power fails, the encryption process can safely and accurately resume where it was interrupted. However, this option can cause initial encryption to take several times longer to complete. This is also useful when encrypting USB devices. Interrupting encryption by removing a USB device during encryption can corrupt the device and require that it be reformatted. Encrypting with Power Failure Safety mode permits you to remove the USB device during encryption and resume encryption once it is reinserted.