That depends. If you have multiple large projects open at the same time, it'll eat a lot of RAM, even if it won't be too CPU intensive.
I run it on a ThinkPad that has 32 GB of RAM, when I have about 6-7 instances of the IDE open and all of these services running locally (generally Java projects, the largest of which is around 4000+ source files), then it gets close to the resource limits.