Every modern SATA SSD will max out at around 550 MB/s read and 530 MB/s write since the speed of the SSD's have long since passed the maximum speed of the SATA interface, even the cheap ones are the same speed. Where you'll see differences are in the access time (especially for large amounts of small files) and transfer of very large files as the ability to cache large files depends on the cache and processing power of the drive. Having said that, nicer SSD's will also have neat things like hardware encryption to secure your files and they'll come with software to transfer your HDD to the SSD (This one comes with terrible software, Samsung Magician, but it's a fantastic drive).