I don't know about this feature but does disabling application can help to reduce my devices RAM usage?
While basically agreeing with Dan, it depends on the app you disable. Some of the pre-installed bloatware runs services in the background, which are quite unlikely to be killed by the OOM (Out Of Memory) "manager". So disabling such an app, other apps can benefit from it: Memory no longer consumed by the disabled app is available to other processes, and their likelyness to be killed due to "memory shortness" is reduced.
Whether you really feel a difference is depending on how much RAM your device is equipped with: on devices with a small amount of memory it "counts more", with 2 GB and more RAM to command you might not notice (except for the battery effect Dan already described).
Not really. Android treats the RAM like a big cache of apps that have run recently. It doesn't remove things from RAM just to make free space, because free RAM doesn't provide any benefit: it just makes it more likely that Android would have to use more power loading the same app from storage again next time you want it. Android only removes processes from RAM when the foreground app needs more RAM.
When you think of it this way, you'll see that nothing usefully reduces your RAM usage, because Android will keep all the RAM full anyway. Disabling applications has two uses:
- It removes the app from the app drawer, so you don't have to see it (and maybe click it by accident).
- It stops the app running down the battery by running in the background, maybe stopping the device going to sleep.