Replacing the PS3's hard drive is a matter of swapping the built-in drive with a new one. Fortunately, Sony hasn't introduced any limitations or restrictions on this point. You can use any 2.5” Serial ATA hard drive that fits into the 9.5 mm z-height format.
However, it's important to know that many 750 GB and 1 TB 2.5” hard drives cannot be used. The highest capacity drives you can find today are 750 GB models, but you’ll get more bang for the buck if you go with 500 GB or 640 GB. We used Toshiba's MK6465GSX, a 5,400 RPM, 2.5” SATA drive with a 640 GB capacity.
Upgrade an Existing PS3 Slim
The PlayStation 3 Slim only needs its firmware to start up. All other data remains on the hard drive. If you buy a new PS3 and decide to upgrade the hard drive right away, then you don’t need to read the next page, which describes the backup process. Creating a backup will copy the existing firmware and all data on the hard drive onto a USB 2.0 storage device. Be sure that your portable drive or memory stick provides sufficient free capacity to hold everything already stored on the factory PS3 drive. Keep in mind that this may be up to 250 GB, so don't assume a flash drive will do the trick. Also be sure you have enough time, as this may take up to a few hours for a complete backup and restore.
Upgrade a New PS3 Slim
If you're upgrading a brand new PS3, then the process is easier. You can go ahead and replace the hard drive straight away. All you need to do is download the latest firmware from Sony’s Web site (here, version 3.3 is 170MB) and copy it onto a USB storage device. Be sure you put the firmware into a folder called PS3/UPDATE.