Q Can I install a third-party SSD (solid-state disk) in my Mac? Do I need any additional software to support it?
A Yes you can, if you ensure that it will physically sit in the case properly and securely.
Many SSDs are supplied in different packages from hard drives, and you will first need to ensure that the SSD that you want to install is either compatible with the innards of your Mac, or comes with an adaptor to make it so.
Another important consideration is TRIM support, which ensures that freed areas of the storage space are made available for reuse. Some third-party products may have built-in or supplied support for this. However, one of the new improvements in Yosemite 10.10.4 is that OS X can now support TRIM on third-party SSDs.
This is not automatic, though. First, the SSD must be connected via SATA, and must support AHCI (which your Mac should be capable of). You will need to check this with the supplier. Then, once the SSD is installed, you will need to enable TRIM for it, either by buying a utility to do this, or for free you can type in Terminal’s command line
sudo trimforce enable
You will then be prompted to enter your admin user’s password. Once that has completed, restart, and your SSD should now run as briskly as intended.