Most versions of PerfectDisk offer a free trial period that allows you to test the optimization features before committing to a purchase.
If you are specifically looking for "Build 312" with a "serial key" via Google, you are likely looking for a way to unlock the full version of this older software. Here is an honest breakdown of the software itself and the risks associated with that search. Most versions of PerfectDisk offer a free trial
By following best practices and using a valid serial key, you can successfully install and activate Raxco PerfectDisk Pro 12.5 Build 312 x86/x64. Most versions of PerfectDisk offer a free trial