In technical terms, what is the correct way to refer to a computer's Clipboard in Spanish? The automated translators say it's "Portapapeles"
Yes, portapapeles is the correct translation; here it is its meaning, according to the RAE:
As you can see, portapapeles is a temporary deposit in a computer's memory to store information for a later use.
As a historical note, the word portapapeles was only recently accepted by the RAE and it will officially "appear in society" in the 23rd edition of the DRAE.