The way I understand it is that on a hybrid drive a piece of software in the controller moves frequently used files to the SSD part of the drive, keeping the rest of the files on the platters. As it needs to 'learn' which files are often used, the performance improvement will not be seen right after installing but this will occur at a later stage. I've looked into getting one for retrofitting in a laptop but will most likely go for a SSD instead. The performance benefit from a hybrid drive is not as large as is possible from a SSD and as the SSD part is relatively small, you will most likely find that unless you're the type who only uses a computer for simple tasks, the SSD section will never hold all the files you'd want to keep there (if you could have a say in that..).