Will PS4 synchronize save data between two PS4's

Question

My brother has a PS4 with lots of digital games. He activated his console as primary because my niece also plays those games. So my console is secondary.

If I download those games from his account I wouldn't be able to play.

My idea is to download games from his account on a secondary console (my console) and play them using the same account, i.e. my brother's account.

Will this affect his game data? I have seen it starts fresh games on my console. If it synchronizes will it spoil both our data?

Answer 1

TL;DR

It might affect his data, but most likely won't. The feature can also be disabled.

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The PS4's save data synchronisation feature works like this:

1. Your brother must be subscribed to PS Plus (this is a paid membership) in order to synchronize save data to the cloud.
2. Only uploads are done automatically. Downloads must be performed manually.
3. Saves are only uploaded when the PS4 is in Rest Mode, and the feature can be disabled in: Settings > Application Saved Data Management > Auto-Upload, either on a per-game basis, or for the entire console.

Since the PS4 doesn't automatically download save data, your brother probably won't notice you playing on his account. This will change if he ever needs to download an older save file from the cloud. Thus I recommend turning the Auto-Upload feature off.