From a database point of view
The answer to your question is YES. The update will take place. The database does not check the previous value, it only sets the new value.
As this happen in memory (and will only be written to the datafiles after a commit is issued) the performance would not be an issue.
From an ORM perspective
Normally you will have an Object representing a single row of the database (it can be a lot more complex than that, but let's keep it simple). This object is managed in memory (at the app server level) and only the latest commited version of that object will actually make it to the database at a certain point.
That may explain the different behaviour.
Now, let's not compare a cargo ship with a 3D printer. The fact that you can send 3D printers using cargo ships doesn't mean that there may be any kind of comparison between them.
I hope this clarified some concepts.