On mine, holding Home offers the Task Manager in bottom left. Including RAM manager. I range anywhere from 0.63-0.92GB/1.33GB of memory usage. Ignore the third party system hogs.
So far, think if you have lots of background chatter like Skype, Facebook, Steam and such it leaves even less room for other tasks. On a 1GB device I would be getting way too close to the upper boundary of 800-850MB or so usable memory. Which again leaves me thinking the Tab 3 7.0 LTE and the Tab 3 8.0 are the best general-use and social tablets from Samsung for now. The regular 7.0 and the 10.1 with 1GB are more likely to have multi tasking lag. A pity since the 10.1's chip is even faster than the 7.0 LTE, without 1.5-2.0GB it can be crippled....