Mac OS X is a slick, powerful operating system, but there’s a cost to all that gloss. Most users don’t ever bother to check, but many of the apps they use every day are notorious RAM-gobblers, eating up huge amounts of system memory and making even brand new Macs feel like they’re running slowly. Here’s a look at why you should keep an eye on your Mac’s memory usage, how to monitor it, and which apps are the worst offenders when it comes to memory drain.