How can I determine how much total RAM my device actually has? I bought a SIM locked ZTE v790 in Egypt. It tells me that it has 181MB of RAM, but it supposed to be 512MB.

Is there a way to check how much RAM my device physically has before deciding to get it replaced?
I know this is an old questions but it comes up first in Google so I thought I would put a simple answer.

Depending on the version of Android:


Settings > Applications > Running services
or Settings > Apps > Running services
or Settings > More > Application Manager > Running (at the top)
or Settings > System > Developer Options > Running services


At the bottom you will see RAM, used and free.  Add both number together to get total usable RAM for the device. Note that this might be less than the RAM advertised for the phone model, as the system may reserve some of the RAM for itself as explained in other answers.

Cheers