It depends on a few things. Encrypting a disk CAN make it slower. For example, if you have an SSD capable of 500mb/sec and then do full disk encryption on it using some crazy long algorithm you might get FAR below that max of 500mb/sec.

Does encryption slow Ubuntu?

Yes, but typically a negligible performance impact. Something a casual desktop user wouldn’t notice. In ubuntu desktop I’d highly suggest it for your home directory at least, assuming it’s setup with its own partition.

Does encryption slow down laptop?

, Founder and CTO of SafeBoot Corp, makers of Hard Disk Encryption products. No, it doesn’t slow down the “computer” (CPU) at all – it does however slow down the read/write speeds of your hard disk. Depending on the program, and what kind of disk it is, read/write could slow down anything from nothing to 30%.